PSLE Henry had a total of 180 long and short rulers. After selling an equal number of both types, he had
35 of the long rulers and
45 of the short ones left. What was the total number of rulers sold?
Fraction of the long rulers sold
= 1 -
35 =
25 Fraction of the short rulers sold
= 1 -
45 =
15 The number of long rulers and short rulers sold is the same.
Make the numerators the same.
LCM of 2 and 1 = 2
25 Long rulers =
15 Short rulers
2x15x1 Long rulers =
1x25x2 Short rulers
25 Long rulers =
210 Short rulers
|
Long |
Short |
Total |
Before |
5 u |
10 u |
15 u |
Change |
- 2 u |
- 2 u |
- 4 u |
After |
3 u |
8 u |
11 u |
Total number of rulers at first
= 5 u + 10 u
= 15 u
15 u = 180
1 u = 180 ÷ 15 = 12
Total number of rulers sold
= 2 u + 2 u
= 4 u
= 4 x 12
= 48
Answer(s): 48