PSLE Owen had a total of 300 short and long rulers. After selling an equal number of both types, he had
45 of the short rulers and
15 of the long ones left. What was the total number of rulers left?
Fraction of the short rulers sold
= 1 -
45 =
15 Fraction of the long rulers sold
= 1 -
15 =
45 The number of short rulers and long rulers sold is the same.
Make the numerators the same.
LCM of 1 and 4 = 4
15 Long rulers =
45 Short rulers
1x45x4 Long rulers =
4x15x1 Short rulers
420 Long rulers =
45 Short rulers
|
Long |
Short |
Total |
Before |
20 u |
5 u |
25 u |
Change |
- 4 u |
- 4 u |
- 8 u |
After |
16 u |
1 u |
17 u |
Total number of rulers at first
= 20 u + 5 u
= 25 u
25 u = 300
1 u = 300 ÷ 25 = 12
Total number of rulers left
= 16 u + 1 u
= 17 u
= 17 x 12
= 204
Answer(s): 204