PSLE Sam had a total of 341 red and blue pens. After selling an equal number of both types, he had
14 of the red pens and
15 of the blue ones left. What was the total number of pens sold?
Fraction of the red pens sold
= 1 -
14 =
34 Fraction of the blue pens sold
= 1 -
15 =
45 The number of red pens and blue pens sold is the same.
Make the numerators the same.
LCM of 3 and 4 = 12
34 Long pens =
45 Short pens
3x44x4 Long pens =
4x35x3 Short pens
1216 Long pens =
1215 Short pens
|
Long |
Short |
Total |
Before |
16 u |
15 u |
31 u |
Change |
- 12 u |
- 12 u |
- 24 u |
After |
4 u |
3 u |
7 u |
Total number of pens at first
= 16 u + 15 u
= 31 u
31 u = 341
1 u = 341 ÷ 31 = 11
Total number of pens sold
= 12 u + 12 u
= 24 u
= 24 x 11
= 264
Answer(s): 264