PSLE The ratio of the number of dresses to that of vests in a boutique was 7 : 1 in the end. After 20 vests were sold, the ratio of the number of dresses to that of vests became 11 : 1. What was the total number of dresses and vests in the boutique in the end?
|
Dresses |
Vests |
Total |
Before |
7x11 = 77 u |
1x11 = 11 u |
88 u |
Change |
|
- 20 |
|
After |
11x7 = 77 u |
1x7 = 7 u |
84 u |
The number of dresses remains unchanged. Make the number of dresses the same.
LCM of 11 and 7 is 77.
Number of vests sold
= 11 u - 7 u
= 4 u
1 u = 20 ÷ 4 = 5
Total number of dresses and vests in the end
= 77 u + 7 u
= 84 u
= 84 x 5
= 420
Answer(s): 420