Evelyn bought 69 pens and Zeph bought 87 pens. After Zeph used
35 times as many pens as Evelyn, he was left with thrice as many pens as Evelyn. How many pens did each of them have in the end?
- Evelyn
- Zeph
| |
Make p the same.
(1)x3 = (3) |
Evelyn
(1) |
Zeph
(2) |
| Before |
207 |
69 |
87 |
| Change |
- 15 u |
- 5 u |
- 3 u |
| After |
3 p |
1 p |
3 p |
(a)
69 - 5 u = 1 p --- (1)
87 - 3 u =
3 p --- (2)
(1)
x3
207 - 15 u =
3 p --- (3)
(3) = (2)
87 - 3 u = 207 - 15 u
15 u - 3 u = 207 - 87
12 u = 120
1 u = 120 ÷ 12 = 10
Number of pens that Evelyn had in the end
= 69 - 5 u
= 69 - 5 x 10
= 69 - 50
= 19
(b)
1 p = 19
Number of pens that Zeph had in the end
= 3 p
= 3 x 19
= 57
Answer(s): (a) 19; (b) 57
