PSLE Pierre had a total of 119 blue and red pens. After selling an equal number of both types, he had
25 of the blue pens and
34 of the red ones left. What was the total number of pens sold?
Fraction of the blue pens sold
= 1 -
25 =
35 Fraction of the red pens sold
= 1 -
34 =
14 The number of blue pens and red pens sold is the same.
Make the numerators the same.
LCM of 3 and 1 = 3
35 Long pens =
14 Short pens
3x15x1 Long pens =
1x34x3 Short pens
35 Long pens =
312 Short pens
|
Long |
Short |
Total |
Before |
5 u |
12 u |
17 u |
Change |
- 3 u |
- 3 u |
- 6 u |
After |
2 u |
9 u |
11 u |
Total number of pens at first
= 5 u + 12 u
= 17 u
17 u = 119
1 u = 119 ÷ 17 = 7
Total number of pens sold
= 3 u + 3 u
= 6 u
= 6 x 7
= 42
Answer(s): 42