12 of the children in a school were girls and the rest were boys.
34 of the girls and
15 of the boys took part in a school event. 315 children did not take part. How many more boys were needed to take part in the school event so that it would be equal to the same number of girls who took part in the event?
Girls |
Boys |
1x20 = 20 u |
1x20 = 20 u |
Took part |
Did not take part |
Took part |
Did not take part |
3x5 |
1x5 |
1x4 |
4x4 |
15 u |
5 u |
4 u |
16 u |
Since
12 of the children in a school were girls and the rest were boys, the total number of girls and boys is the same.
The total number of girls is repeated and the total number of boys is repeated.
Make the total number of girls and the total number of boys the same since they are equal. LCM of 4 and 5 is 20.
Number of children who did not take part
= 5 u + 16 u
= 21 u
21 u = 315
1 u = 315 ÷ 21 = 15
Number of more boys that were needed to take part in the school event so that it would be equal to the same number of girls who took part in the event
= 15 u - 4 u
= 11 u
= 11 x 15
= 165
Answer(s): 165