There were twice as many girls as boys at a conference. After 15 boys left the conference, there were five times as many girls as boys who remained behind. How many girls were there at the conference?
| |
Girls |
Boys |
| Before |
2x5 =
10 u |
1x5 =
5 u |
| Change |
|
- 15 |
| After |
5x2 =
10 u |
1x2 =
2 u |
The number of girls remained unchanged. Make the number of girls the same. LCM of 2 and 5 is 10.
Decrease in the number of boys
= 5 u - 2 u
= 3 u
3 u = 15
1 u = 15 ÷ 3 = 5
Number of girls
= 10 u
= 10 x 5
= 50
Answer(s): 50
