Cindy had 60 more pens than Betty. After Betty gave away
15 of her pens, Cindy had five times as many pens as Betty. How many pens did Betty have at first?
| |
Cindy |
Betty |
Comparing Cindy
and Betty at first |
60 more |
|
| Before |
20 u |
5 u |
| Change |
|
- 1 u |
| After |
|
4 u |
Comparing Cindy
and Betty in the end |
5x4 =
20 u |
1x4 =
4 u |
The number of pens that Cindy had at first and in the end remains unchanged. Make the number of pens that Cindy had the same. LCM of 20 and 5 is 20.
Number of pens that Cindy had more than Betty at first
= 20 u - 5 u
= 15 u
15 u = 60
1 u = 60 ÷ 15 = 4
Number of pens that Betty had at first
= 5 u
= 5 x 4
= 20
Answer(s): 20
