PSLE Zeph had a total of 306 short and long erasers. After selling an equal number of both types, he had
15 of the short erasers and
23 of the long ones left. What was the total number of erasers left?
Fraction of the short erasers sold
= 1 -
15 =
45 Fraction of the long erasers sold
= 1 -
23 =
13 The number of short erasers and long erasers sold is the same.
Make the numerators the same.
LCM of 4 and 1 = 4
45 Long erasers =
13 Short erasers
4x15x1 Long erasers =
1x43x4 Short erasers
45 Long erasers =
412 Short erasers
|
Long |
Short |
Total |
Before |
5 u |
12 u |
17 u |
Change |
- 4 u |
- 4 u |
- 8 u |
After |
1 u |
8 u |
9 u |
Total number of erasers at first
= 5 u + 12 u
= 17 u
17 u = 306
1 u = 306 ÷ 17 = 18
Total number of erasers left
= 1 u + 8 u
= 9 u
= 9 x 18
= 162
Answer(s): 162