PSLE Sean had a total of 111 short and long erasers. After selling an equal number of both types, he had
35 of the short erasers and
16 of the long ones left. What was the total number of erasers sold?
Fraction of the short erasers sold
= 1 -
35 =
25 Fraction of the long erasers sold
= 1 -
16 =
56 The number of short erasers and long erasers sold is the same.
Make the numerators the same.
LCM of 2 and 5 = 10
25 Long erasers =
56 Short erasers
2x55x5 Long erasers =
5x26x2 Short erasers
1025 Long erasers =
1012 Short erasers
|
Long |
Short |
Total |
Before |
25 u |
12 u |
37 u |
Change |
- 10 u |
- 10 u |
- 20 u |
After |
15 u |
2 u |
17 u |
Total number of erasers at first
= 25 u + 12 u
= 37 u
37 u = 111
1 u = 111 ÷ 37 = 3
Total number of erasers sold
= 10 u + 10 u
= 20 u
= 20 x 3
= 60
Answer(s): 60