12 of the pupils in a school were girls and the rest were boys.
25 of the girls and
14 of the boys took part in a school event. 312 pupils took 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 |
2x4 |
3x4 |
1x5 |
3x5 |
8 u |
12 u |
5 u |
15 u |
Since
12 of the pupils 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 5 and 4 is 20.
Number of pupils who took part
= 8 u + 5 u
= 13 u
13 u = 312
1 u = 312 ÷ 13 = 24
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
= 8 u - 5 u
= 3 u
= 3 x 24
= 72
Answer(s): 72