Christopher bought 75 pens and Ahmad bought 94 pens. After Ahmad used
35 times as many pens as Christopher, he was left with twice as many pens as Christopher. How many pens did each of them have in the end?
- Christopher
- Ahmad
| |
Make p the same.
(1)x2 = (3) |
Christopher
(1) |
Ahmad
(2) |
| Before |
150 |
75 |
94 |
| Change |
- 10 u |
- 5 u |
- 3 u |
| After |
2 p |
1 p |
2 p |
(a)
75 - 5 u = 1 p --- (1)
94 - 3 u =
2 p --- (2)
(1)
x2
150 - 10 u =
2 p --- (3)
(3) = (2)
94 - 3 u = 150 - 10 u
10 u - 3 u = 150 - 94
7 u = 56
1 u = 56 ÷ 7 = 8
Number of pens that Christopher had in the end
= 75 - 5 u
= 75 - 5 x 8
= 75 - 40
= 35
(b)
1 p = 35
Number of pens that Ahmad had in the end
= 2 p
= 2 x 35
= 70
Answer(s): (a) 35; (b) 70
