PSLE Carl had a total of 646 long and short erasers. After selling an equal number of both types, he had
16 of the long erasers and
14 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 -
14 =
34 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 =
34 Short erasers
5x36x3 Long erasers =
3x54x5 Short erasers
1518 Long erasers =
1520 Short erasers
|
Long |
Short |
Total |
Before |
18 u |
20 u |
38 u |
Change |
- 15 u |
- 15 u |
- 30 u |
After |
3 u |
5 u |
8 u |
Total number of erasers at first
= 18 u + 20 u
= 38 u
38 u = 646
1 u = 646 ÷ 38 = 17
Total number of erasers sold
= 15 u + 15 u
= 30 u
= 30 x 17
= 510
Answer(s): 510