Eight minutes ago, 75% of the pupils in a hall were girls. 27 more pupils entered the hall. As a result, the number of girls increased by 25% and the number of boys increased by 80%. How many pupils are in the hall now?
| |
Girls |
Boys |
Total |
| Before |
4 u |
1 u |
5 u |
| Change |
+ 1 u |
+ 0.8 u |
+ 1.8 u |
| After |
5 u |
1.8 u |
6.8 u |
75% =
75100 =
34Number of more girls who entered the hall
= 25% x 4 u
=
25100 x 4 u
= 1 u
Number of more boys who entered the hall
= 80% x 1 u
=
80100 x 1 u
= 0.8 u
Total number of more pupils who entered the hall
= 1 u + 0.8 u
= 1.8 u
1.8 u = 27
1 u = 27 ÷ 1.8 = 15
Number of pupils in the hall now
= 5 u + 1.8 u
= 6.8 u
= 6.8 x 15
= 102
Answer(s): 102
