PSLE The ratio of the number of skirts to that of sweaters in a shopping centre was 4 : 1 at first. After 12 sweaters were sold, the ratio of the number of skirts to that of sweaters became 7 : 1. What was the total number of skirts and sweaters in the shopping centre at first?
|
Skirts |
Sweaters |
Total |
Before |
4x7 = 28 u |
1x7 = 7 u |
35 u |
Change |
|
- 12 |
|
After |
7x4 = 28 u |
1x4 = 4 u |
32 u |
The number of skirts remains unchanged. Make the number of skirts the same.
LCM of 7 and 4 is 28.
Number of sweaters sold
= 7 u - 4 u
= 3 u
1 u = 12 ÷ 3 = 4
Total number of skirts and sweaters at first
= 28 u + 7 u
= 35 u
= 35 x 4
= 140
Answer(s): 140