PSLE Liam had a total of 272 blue and red pens. After selling an equal number of both types, he had
12 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 -
12 =
12 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 1 and 5 = 5
12 Long pens =
56 Short pens
1x52x5 Long pens =
5x16x1 Short pens
510 Long pens =
56 Short pens
|
Long |
Short |
Total |
Before |
10 u |
6 u |
16 u |
Change |
- 5 u |
- 5 u |
- 10 u |
After |
5 u |
1 u |
6 u |
Total number of pens at first
= 10 u + 6 u
= 16 u
16 u = 272
1 u = 272 ÷ 16 = 17
Total number of pens sold
= 5 u + 5 u
= 10 u
= 10 x 17
= 170
Answer(s): 170