PSLE Lee had a total of 90 long and short rulers. After selling an equal number of both types, he had
56 of the long rulers and
13 of the short ones left. What was the total number of rulers sold?
Fraction of the long rulers sold
= 1 -
56 =
16 Fraction of the short rulers sold
= 1 -
13 =
23 The number of long rulers and short rulers sold is the same.
Make the numerators the same.
LCM of 1 and 2 = 2
16 Long rulers =
23 Short rulers
1x26x2 Long rulers =
2x13x1 Short rulers
212 Long rulers =
23 Short rulers
|
Long |
Short |
Total |
Before |
12 u |
3 u |
15 u |
Change |
- 2 u |
- 2 u |
- 4 u |
After |
10 u |
1 u |
11 u |
Total number of rulers at first
= 12 u + 3 u
= 15 u
15 u = 90
1 u = 90 ÷ 15 = 6
Total number of rulers sold
= 2 u + 2 u
= 4 u
= 4 x 6
= 24
Answer(s): 24