Twenty minutes ago, 60% of the pupils in a hall were girls. 39 more pupils entered the hall. As a result, the number of girls increased by 20% and the number of boys increased by 80%. How many pupils are in the hall now?
| |
Girls |
Boys |
Total |
| Before |
5 u |
2 u |
7 u |
| Change |
+ 1 u |
+ 1.6 u |
+ 2.6 u |
| After |
6 u |
3.6 u |
9.6 u |
60% =
60100 =
35Number of more girls who entered the hall
= 20% x 5 u
=
20100 x 5 u
= 1 u
Number of more boys who entered the hall
= 80% x 2 u
=
80100 x 2 u
= 1.6 u
Total number of more pupils who entered the hall
= 1 u + 1.6 u
= 2.6 u
2.6 u = 39
1 u = 39 ÷ 2.6 = 15
Number of pupils in the hall now
= 6 u + 3.6 u
= 9.6 u
= 9.6 x 15
= 144
Answer(s): 144
