Andrew bought 54 pencils and Billy bought 97 pencils. After Billy used
25 times as many pencils as Andrew, he was left with thrice as many pencils as Andrew. How many pencils did each of them have in the end?
- Andrew
- Billy
| |
Make p the same.
(1)x3 = (3) |
Andrew
(1) |
Billy
(2) |
| Before |
162 |
54 |
97 |
| Change |
- 15 u |
- 5 u |
- 2 u |
| After |
3 p |
1 p |
3 p |
(a)
54 - 5 u = 1 p --- (1)
97 - 2 u =
3 p --- (2)
(1)
x3
162 - 15 u =
3 p --- (3)
(3) = (2)
97 - 2 u = 162 - 15 u
15 u - 2 u = 162 - 97
13 u = 65
1 u = 65 ÷ 13 = 5
Number of pencils that Andrew had in the end
= 54 - 5 u
= 54 - 5 x 5
= 54 - 25
= 29
(b)
1 p = 29
Number of pencils that Billy had in the end
= 3 p
= 3 x 29
= 87
Answer(s): (a) 29; (b) 87
