PSLE Pierre had a total of 289 blue and red pens. After selling an equal number of both types, he had
35 of the blue pens and
56 of the red ones left. What was the total number of pens left?
Fraction of the blue pens sold
= 1 -
35 =
25 Fraction of the red pens sold
= 1 -
56 =
16 The number of blue pens and red pens sold is the same.
Make the numerators the same.
LCM of 2 and 1 = 2
25 Long pens =
16 Short pens
2x15x1 Long pens =
1x26x2 Short pens
25 Long pens =
212 Short pens
|
Long |
Short |
Total |
Before |
5 u |
12 u |
17 u |
Change |
- 2 u |
- 2 u |
- 4 u |
After |
3 u |
10 u |
13 u |
Total number of pens at first
= 5 u + 12 u
= 17 u
17 u = 289
1 u = 289 ÷ 17 = 17
Total number of pens left
= 3 u + 10 u
= 13 u
= 13 x 17
= 221
Answer(s): 221