There were thrice as many girls as boys at a party. After 20 boys left the party, there were five times as many girls as boys who remained behind. How many girls were there at the party?
| |
Girls |
Boys |
| Before |
3x5 =
15 u |
1x5 =
5 u |
| Change |
|
- 20 |
| After |
5x3 =
15 u |
1x3 =
3 u |
The number of girls remained unchanged. Make the number of girls the same. LCM of 3 and 5 is 15.
Decrease in the number of boys
= 5 u - 3 u
= 2 u
2 u = 20
1 u = 20 ÷ 2 = 10
Number of girls
= 15 u
= 15 x 10
= 150
Answer(s): 150
