Maths Problems 14 Aug 09

1. In a concert hall, 1/7 of the audience were children. 75% of the adults were women. There were 280 more women than children.

(a) How many women were there in the hall? [2]
(b) During the interval, some men left the hall. As a result, 12% of the remaining audiences were men. How many men left the hall? [3]

2. The base of the container is a square of side 8 cm. Twelve 4-cm cubes are placed in the container. Water is then poured into the container until it is 5/6 full. When all the cubes are removed without any loss of water, the water level drops to 2/3 the height of the container.

(a) Find the volume of the twelve cubes. (1)
(b) Find the height of the container. (4)

3. Amy, Beth and Carrie have some money. If Amy gives $3.50 to Beth, the two girls will have an equal amount of money. If Beth gives $3.50 to Amy, Amy will have thrice as much money as Beth. Carrie’s share is the sum of the other two girls.How much money do they have altogether? (4)

4. Alice left Town X at 8.30 a.m. and travelled towards Town Y at an average speed of 90 km/h. Belinda left Town X 45 minutes later and travelled towards Town Y along the same route at an average speed of 84 km/h.

a) How far apart were they at 10 a.m.? (1m)
b) If Belinda increased her speed by 18 km/h after 10 a.m., how long would it be before she overtakes Alice? (3)

5. A factory was required to produce a certain number of toys in four days.
On the first day, it produced 1/5 of the required number of toys.
On the second day, it produced another 20 toys.
On the third day, it produced as many toys as those produced on the first two days.
On the fourth day, it completed the remaining 8 toys.How many toys did the factory produce in the four days? (4)

NHo8

Supp Class is on on Tuesday 11 August 09

Dear Pupils (6-9)

There will be supplementary class this Tuesday (11 Aug 09) from 1330 to 1500. Please help to disseminate to all.

See you soon
Mdm Toh

Maths Problems 10 Aug 09

1. Mr Lee paid $671.30 for some pants and T-shirts. A pants cost $29.90 and a T-shirt was $8 cheaper than the pants. If he bought 7 more T-shirts than pants, how many T-shirts did he buy? (4m)

2. There were 1700 pupils in Primary 4, Primary 5 and Primary 6. However, only 1450 pupils passed their NAPFA test. 7/8 of the boys passed the test and 4/5 of the girls passed the test. How many girls passed the test? (4m)

Jurong

3. Box A and Box B contained only blue and red marbles. In Box A, the ratio of the number of blue marbles to the number of red marbles was 7 : 3. In Box B, the ratio of the number of blue marbles to the number of red marbles was 3 : 2. There were 4 times as many marbles in Box A as in Box B.

(a) What was the ratio of the number of blue marbles in Box A to the number of red marbles in Box B? Give your answer in its simplest form. (3m)

(b) When 90 red marbles were put into Box B, the ratio of the number of blue marbles to the number of red marbles in Box B became 2 : 3. How many red marbles were there in Box B then? (2m)

4. At 8 a.m., a truck started from Town A and travelled towards Town B at a speed of 50 km/h for the whole journey. At 10 a.m., a car started from Town B and travelled towards Town A. The speed of the car remained the same until it passed the truck at 12 noon. At this point, the truck had travelled 4/9 of the journey. After passing the truck, the car decreased its speed by 5 km/h and travelled at the new speed for the remaining journey. At what time did the car reach Town A? (5m)

5. A transport company charges $6.50 for parcels delivered on time and $4.50 for parcels delivered late. In June the company collected $8 330. For every 14 parcels delivered, 3 were delivered late and 11 were delivered on time.

(a) What was the total number of parcels delivered late? (3m)
(b) How much less money did the company collect in June because of parcels delivered late?(2m)

YH

Maths Problems 9 Aug 09

1. Mary bought some files, storybooks and assessment books. Each storybook cost $17.50. She spent 1/9 of her money on files. The ratio of the amount spent on assessment books to the amount spent on story books is 5 : 7. The ratio of the number of files bought to the number of storybooks bought is 3 : 2. She also bought 1/2 as many storybooks as assessment books. How much did she pay for an assessment book? (5m)

2. Sam went shopping at a department store. He spent 1/5 of his money on a sofa set and $786 on a washing machine. Later, he spent 1/8 of his remaining amount on a dining table. If the amount of money left was $86.35 more than half of the amount he had at first, how much money did Sam have at first? (5m)

3. Mrs Tan paid $35.70 for 2 kg of grapes and 5 kg of pears. If 3/4kg of pears cost as much as 3/5 kg of grapes, how much did she pay for 1 kg of grapes? (5m)

4. The table shows the rate of a Taxi fare in Singapore. Mr Lee took a taxi home after watching mid-night movie at a cinema and paid $ 11.70 to the taxi driver. What could be the maximum distance travelled in km? (5m)

Taxi fare Cost
Flag Down ( Inclusive of 1st km or less) $2.80
Every 385 metres thereafter or less $0.20
Midnight Surcharge 50% of metered fare

5. There were 32 students in the Violin Club. 75 % of the students were girls. Some more boys joined the Violin Club and the percentage of boys increased to 40%. How many more boys joined the club? (4m)

Jurong

Maths Problems 8 Aug 09

1. Three girls Anne, Betty and Carrie had 288 badges altogether. Anne gave some of the badges to Betty and Betty’s badges were doubled. Then Betty gave some of her badges to Carrie and Carrie’s badges were doubled. As a result, the three girls had an equal number of badges each. How many badges did each girl have at first? (4m)

2. In the beginning of the year, 80% of the pupils in a school were girls. When 530 new pupils were admitted to the school, the number of girls increased by 25% and the number of boys was doubled. How many pupils were in the school at first? (4m)

3. Four children, Arnold, Bernard, Carl and Darlene shared $720. Arnold received 1/2
of the total amount of money received by Bernard, Carl and Darlene. Bernard received 2/3 of the total amount of money received by Carl and Darlene. Carl received 3 times as much money as Darlene.
(a) How much money did Darlene receive? (3m)
(b) What fraction of Arnold’s money is Darlene’s money if Arnold gave $20 to Darlene? (1m)

4. Mrs Lim bought a total of 520 apples and oranges in the ratio 3 : 5. After she gave away an equal number of each type of fruits, the ratio of the number of apples left to the number of oranges left was 3 : 8. How many apples had she left? (3m)

5. Jackie has 50 fifty-cent and twenty-cent coins altogether. The value of the twenty-cent coins is $0.90 more than that of the fifty-cent coins. How many twenty-cent coins does he have? (3m)



JunYuan

Maths Problems 7 Aug 09

1. Joanne had 20-cent coins and 50-cent coins in a box. The percentage of the number of 20-cent coins was 40% of the total number of coins Joanne had. Joanne took out ten 50-cent coins and put in 20-cent coins of the same value. The percentage of the number of 20-cent coins became 50% of the total number of coins Joanne had. What was the amount of money in the box?

2. Last year 20% of the people who visited an IT show were children. 3/5 of the adults were men and the rest were women. This year, the number of children who visited the IT show has increased 10% from last year and there are 256 women more than children. The number of adults who visited the IT show remained the same but now 1/3 of the adults were women.
a) find the ratio of the number of children to the number of men to the number of the women who attended the IT show last year. (2m)
b) find the total number of people who visited the IT show this year. (3m)

3. Mr Raju was asked to deliver 1600 boxes of biscuits to Mr Lau. For every box of biscuits safely delivered, Mr Lau paid him 60 cents. But Mr Raju had to pay $1.20 for every box of biscuits damaged during transportation. If Mr Lau paid Mr Raju $927.60 for the job, how many boxes of biscuits were damaged during the journey? (5m)

4. Michael had 750 local and foreign stamps. He gave 3/4 of his local stamps and 1/3 of his foreign stamps to his best friend. He then had 250 stamps left. How many foreign stamps did he have at first? (5m)

5. Clark and Kent have some money. If Clark spends $120 a day and Kent spends
$40 a day, Clark will have $280 left while Kent will have spent all his money. If Clark spends $40 a day and Kent spends $120 a day, Clark will have $600 left when Kent has spent all his money.
(a) How much money does Kent have? (3m)
(b) How much money does Clark have? (2m)

Maths Problems 31 July 09

1. Mother gave Claire and Jane each a certain amount of money to spend.
If Claire spent $90 per day and Jane spent $30 per day, Claire would have $100 left when Jane had spent all her money. If Claire spent $30 per day and Jane $90 per day, Claire spent would have $580 left when Jane had spent all her money. Find the total amount of money given to Claire and Jane.

2. Mary and Jason each have some money. If Mary spent $80 per day and Jason spent $40 per day, Mary will have $500 left when Jason has spent all his money. If Mary spent $40 per day and Jason spent $80 per day, Mary will have $1100 left when Jason has spent all his money. What is the amount of money that Jason has?