PSLE Ethan had a total of 220 short and long rulers. After selling an equal number of both types, he had
13 of the short rulers and
34 of the long ones left. What was the total number of rulers left?
Fraction of the short rulers sold
= 1 -
13 =
23 Fraction of the long rulers sold
= 1 -
34 =
14 The number of short rulers and long rulers sold is the same.
Make the numerators the same.
LCM of 2 and 1 = 2
23 Long rulers =
14 Short rulers
2x13x1 Long rulers =
1x24x2 Short rulers
23 Long rulers =
28 Short rulers
|
Long |
Short |
Total |
Before |
3 u |
8 u |
11 u |
Change |
- 2 u |
- 2 u |
- 4 u |
After |
1 u |
6 u |
7 u |
Total number of rulers at first
= 3 u + 8 u
= 11 u
11 u = 220
1 u = 220 ÷ 11 = 20
Total number of rulers left
= 1 u + 6 u
= 7 u
= 7 x 20
= 140
Answer(s): 140