In April, Jade and Justin had erasers in the ratio 13 : 7. In May, each of them gave away the same number of erasers. Jade then had four times as many erasers as Justin.
- Find the ratio of the number of erasers Justin had in April to the number of erasers he had in May.
- Find the ratio of the total number of erasers both had in April to the total number of erasers both had in May.
| |
Jade |
Justin |
Difference |
| Before |
13x1 =
13 u |
7x1 =
7 u |
6x1 =
6 u |
| Change |
- 5 u |
- 5 u |
|
| After |
4x2 =
8 u |
1x2 =
2 u |
3x2 =
6 u |
(a)
Since Jade and Justin gave away the same number of erasers, the difference in the number of erasers between Jade and Justin at first and in the end remains the same.
Make the difference in the number of erasers at first and in the end the same. LCM of 6 and 3 is 6.
Justin's erasers in April : Justin's erasers in May
7 : 2
(b)
Total number of erasers in April
= 13 u + 7 u
= 20 u
Total number of erasers in May
= 8 u + 2 u
= 10 u
Total erasers in April : Total erasers in May
20 : 10
(÷10)2 : 1
Answer(s): (a) 7 : 2; (b) 2 : 1
