Four minutes ago, 75% of the pupils in a hall were boys. 38 more pupils entered the hall. As a result, the number of boys increased by 25% and the number of girls increased by 90%. How many pupils are in the hall now?
| |
Boys |
Girls |
Total |
| Before |
4 u |
1 u |
5 u |
| Change |
+ 1 u |
+ 0.9 u |
+ 1.9 u |
| After |
5 u |
1.9 u |
6.9 u |
75% =
75100 =
34Number of more boys who entered the hall
= 25% x 4 u
=
25100 x 4 u
= 1 u
Number of more girls who entered the hall
= 90% x 1 u
=
90100 x 1 u
= 0.9 u
Total number of more pupils who entered the hall
= 1 u + 0.9 u
= 1.9 u
1.9 u = 38
1 u = 38 ÷ 1.9 = 20
Number of pupils in the hall now
= 5 u + 1.9 u
= 6.9 u
= 6.9 x 20
= 138
Answer(s): 138
