PSLE Ahmad had a total of 540 blue and red pens. After selling an equal number of both types, he had
13 of the blue pens and
16 of the red ones left. What was the total number of pens sold?
Fraction of the blue pens sold
= 1 -
13 =
23 Fraction of the red pens sold
= 1 -
16 =
56 The number of blue pens and red pens sold is the same.
Make the numerators the same.
LCM of 2 and 5 = 10
23 Long pens =
56 Short pens
2x53x5 Long pens =
5x26x2 Short pens
1015 Long pens =
1012 Short pens
|
Long |
Short |
Total |
Before |
15 u |
12 u |
27 u |
Change |
- 10 u |
- 10 u |
- 20 u |
After |
5 u |
2 u |
7 u |
Total number of pens at first
= 15 u + 12 u
= 27 u
27 u = 540
1 u = 540 ÷ 27 = 20
Total number of pens sold
= 10 u + 10 u
= 20 u
= 20 x 20
= 400
Answer(s): 400