Barbara had 80 more pens than Gwen. After Gwen gave away
25 of her pens, Barbara had five times as many pens as Gwen. How many pens did Gwen have at first?
| |
Barbara |
Gwen |
Comparing Barbara and
Gwen at first |
80 more |
|
| Before |
15 u |
5 u |
| Change |
|
- 2 u |
| After |
15 u |
3 u |
Comparing Barbara and
Gwen in the end |
5x3 =
15 u |
1x3 =
3 u |
Number of pens that Gwen had in the end is repeated. Make the number of pens that Gwen had in the end the same. LCM of 1 and 3 is 3.
Number of pens that Barbara had at first = 15 u
Number of pens that Barbara had more than Gwen at first
= 15 u - 5 u
= 10 u
10 u = 80
1 u = 80 ÷ 10 = 8
Number of pens that Gwen had at first
= 5 u
= 5 x 8
= 40
Answer(s): 40
