PSLE Luke had a total of 129 long and short erasers. After selling an equal number of both types, he had
16 of the long erasers and
25 of the short ones left. What was the total number of erasers sold?
Fraction of the long erasers sold
= 1 -
16 =
56 Fraction of the short erasers sold
= 1 -
25 =
35 The number of long erasers and short erasers sold is the same.
Make the numerators the same.
LCM of 5 and 3 = 15
56 Long erasers =
35 Short erasers
5x36x3 Long erasers =
3x55x5 Short erasers
1518 Long erasers =
1525 Short erasers
|
Long |
Short |
Total |
Before |
18 u |
25 u |
43 u |
Change |
- 15 u |
- 15 u |
- 30 u |
After |
3 u |
10 u |
13 u |
Total number of erasers at first
= 18 u + 25 u
= 43 u
43 u = 129
1 u = 129 ÷ 43 = 3
Total number of erasers sold
= 15 u + 15 u
= 30 u
= 30 x 3
= 90
Answer(s): 90