Rebecca bought 59 pencils and John bought 100 pencils. After John used
35 times as many pencils as Rebecca, he was left with four times as many pencils as Rebecca. How many pencils did each of them have in the end?
- Rebecca
- John
| |
Make p the same.
(1)x4 = (3) |
Rebecca
(1) |
John
(2) |
| Before |
236 |
59 |
100 |
| Change |
- 20 u |
- 5 u |
- 3 u |
| After |
4 p |
1 p |
4 p |
(a)
59 - 5 u = 1 p --- (1)
100 - 3 u =
4 p --- (2)
(1)
x4
236 - 20 u =
4 p --- (3)
(3) = (2)
100 - 3 u = 236 - 20 u
20 u - 3 u = 236 - 100
17 u = 136
1 u = 136 ÷ 17 = 8
Number of pencils that Rebecca had in the end
= 59 - 5 u
= 59 - 5 x 8
= 59 - 40
= 19
(b)
1 p = 19
Number of pencils that John had in the end
= 4 p
= 4 x 19
= 76
Answer(s): (a) 19; (b) 76
