Justin, Ryan and Zane had 252 pens. After Justin used 21 pens and Ryan used
15 of her pens, Justin had four times as many pens left as Ryan. Zane bought another 30 pens, he had twice the number of pens Ryan had left. How many pens did Zane have at first?
| |
Justin |
Ryan |
Zane |
Total |
| Before |
16 u + 21 |
5 u |
8 u - 30 |
252 |
| Change |
- 21 |
- 1 u |
+ 30 |
|
| After |
16 u |
4 u |
8 u |
|
Comparing Justin
and Ryan in the end |
4 |
1 |
|
|
Comparing Zane
and Ryan in the end |
|
1 |
2 |
|
Number of pens that Justin had in the end
= 4 x 4 u
= 16 u
Number of pens that Zane had in the end
= 2 x 4 u
= 8 u
Total number of pens at first
= 16 u + 21 + 5 u + 8 u - 30
= 29 u - 9
29 u - 9 = 252
29 u = 252 + 9
29 u = 261
1 u = 261 ÷ 29 = 9
Number of pens that Zane had at first
= 8 u - 30
= 8 x 9 - 30
= 72 - 30
= 42
Answer(s): 42
