iMaths Practise 3

1. There are 1500 pupils in upper primary in ABC school. 1/4 of the boys and 2/3 of the girls are in lower primary. 60% of the upper primary pupils are boys while the rest are the upper primary girls.

(a) What is the ratio of the total no. of boys to the total no. of girls in the school? (Express your answer in the simplest form)

(b) 900 girls in the lower primary do not wear spectacles. Of all the lower primary pupils, what is the percentage of girls who wears spectacles?


2. Peter has $8 more than Ben. Then, Peter gave 1/4 of his money to Ben. As a result, the ratio of the amount of money Peter had to the amount of money Ben became 5:7. How much money did Peter give to Ben?


3. Harry spent 1/2 of his money on some muffins and 3/5 of his remaining money on 5 pieces of cakes. Each piece of cake cost thrice as much as muffins. How many muffins did he buy?


4. The ratio of Xavier’s savings to Henry’s savings was 6:7.

Xavier and Henry shared the cost of a game set in the ratio 4:5 respectively
Xavier used 2/3 of his saving to pay for his share of the game set. Henry was left with $150 after paying for his share.

a) What was Henry's saving’s before paying for his share of the game set?

b) What was the cost of the game set?




5. There are 160 red marbles and some blue marbles in a box. If 3/8 of the blue marbles is taken out of the box and 50 new red marbles are put into the box, the ratio of the number of red marbles to the number of

blue marbles becomes 7:9. How many blue marbles are there in the box?


*6. A boutique owner bought 1.5 times as many skirts as dresses. She spent $1496 altogether. A dress costs $4 more than a skirt. The total cost of the skirts was $136 more than the total cost of the dresses. Find the cost of 2 skirts and 1 dress.

iMaths Practise 2 Solution

Q1. Case 1
X = unit + 30
Y = unit - 30

Case 2
X = unit + 30 + 18
Y = unit - 30 - 18
unit+30+18 = 4(unit-30-18)
unit+48 = 4units-192
3 units = 240
1 unit = 80
At first, X = unit+30 = 80+30=110

At first,number of beads in Box X was 110.

Q2. In the end, all 3 containers became equal.
So, P=Q=E = 162 divided by 3 = 54
R(Original) = 54 divided by 3 = 18
Q(Before giving R and after receiving from P)= 54+18x2 = 90
Q(Original) = 90 divided by 3 = 30
P(Original) = 54+30x2 = 114

Number of buttons in container P at first = 114.

Q3. In the end,
X = 115
Y = 90
2/3 of Y = 90
Y = 135
X = 115-(90÷2)=70
2/3 of X = 70
X = 70x3/2= 105
Y = 135-(70÷2) = 100
4/5 of Y = 100
Y = 125
X = 105-(100÷4) = 80

AT first, there were 80 marbles in Box X and 125 marbles in Box Y.

Q4. (7+½)x2=15
(15÷2)+½ = 8
Number of chocolate bars that the third child got = 8.

Note
1st child got 32 chocolate bars
2nd child got 16 chocolate bars
3rd child got 8 chocolate bars
4th child got 7 chocolate bars

Total = 63 chocolate bars.

Q5. Women = 1/5
Men + Children = 4/5
Men = 2/5x4/5 = 8/25
Children = 1-1/5-8/25 = 12/25
12/25 of total = 266+266x2 = 798
8/25 of total = 532

Number of men in the hall = 532.

Q6. Cloths = 5/9
Gifts = 1/3
Mother + Left = 1-5/9-1/3 = 1/9
1/9 of the total = $1500+$560 = $2060
Total for Samuel= $2060x9 = $18540

Total for Samuel and Nigel = ($18540/4)x9 = $41715

Q7. 3N + J = 40.80
       2N + 2J = 45.20 (86 - 40.80)
        J - N = 4.4
 Rewriting N as J -4.4
       3J - 13.20 + J = 40.80, J = 54/3 = 13.50

Q8. 0.7 blue + 0.7 red --> 91 (adding both)
7 blue + 7 red --> 910 (times by 10)
1 blue + 1 red --> 130 (divide by 7)