PSLE Jeremy had a total of 273 red and blue pens. After selling an equal number of both types, he had
16 of the red pens and
23 of the blue ones left. What was the total number of pens sold?
Fraction of the red pens sold
= 1 -
16 =
56 Fraction of the blue pens sold
= 1 -
23 =
13 The number of red pens and blue pens sold is the same.
Make the numerators the same.
LCM of 5 and 1 = 5
56 Long pens =
13 Short pens
5x16x1 Long pens =
1x53x5 Short pens
56 Long pens =
515 Short pens
|
Long |
Short |
Total |
Before |
6 u |
15 u |
21 u |
Change |
- 5 u |
- 5 u |
- 10 u |
After |
1 u |
10 u |
11 u |
Total number of pens at first
= 6 u + 15 u
= 21 u
21 u = 273
1 u = 273 ÷ 21 = 13
Total number of pens sold
= 5 u + 5 u
= 10 u
= 10 x 13
= 130
Answer(s): 130