PSLE The ratio of the number of jackets to that of sweaters in a shopping centre was 11 : 7 at first. After 70 sweaters were sold, the ratio of the number of jackets to that of sweaters became 3 : 1. What was the total number of jackets and sweaters in the shopping centre at first?
|
Jackets |
Sweaters |
Total |
Before |
11x3 = 33 u |
7x3 = 21 u |
54 u |
Change |
|
- 70 |
|
After |
3x11 = 33 u |
1x11 = 11 u |
44 u |
The number of jackets remains unchanged. Make the number of jackets the same.
LCM of 3 and 11 is 33.
Number of sweaters sold
= 21 u - 11 u
= 10 u
1 u = 70 ÷ 10 = 7
Total number of jackets and sweaters at first
= 33 u + 21 u
= 54 u
= 54 x 7
= 378
Answer(s): 378