PSLE Wesley had a total of 234 blue and red pens. After selling an equal number of both types, he had
45 of the blue pens and
13 of the red ones left. What was the total number of pens left?
Fraction of the blue pens sold
= 1 -
45 =
15 Fraction of the red pens sold
= 1 -
13 =
23 The number of blue pens and red pens sold is the same.
Make the numerators the same.
LCM of 1 and 2 = 2
15 Long pens =
23 Short pens
1x25x2 Long pens =
2x13x1 Short pens
210 Long pens =
23 Short pens
|
Long |
Short |
Total |
Before |
10 u |
3 u |
13 u |
Change |
- 2 u |
- 2 u |
- 4 u |
After |
8 u |
1 u |
9 u |
Total number of pens at first
= 10 u + 3 u
= 13 u
13 u = 234
1 u = 234 ÷ 13 = 18
Total number of pens left
= 8 u + 1 u
= 9 u
= 9 x 18
= 162
Answer(s): 162