In a school, the ratio of adults to the number of children is 9 : 10.
The ratio of the number of girls to the number of boys is 3 : 2.
There are 78 less boys than girls.
How many people are there in the school?
Adults |
Children |
9 x 1 |
10 x 1 |
|
Girls |
Boys |
|
3 x 2 |
2 x 2 |
9 u |
6 u |
4 u |
The number of children is the combined repeated identity.
Make the number of children the same using the LCM of 10 and 5.
LCM of 10 and 5 = 10
Number of less boys than girls
= 6 u - 4 u
= 2 u
2 u = 78
1 u = 78 ÷ 2 = 39
Number of people
= 9 u + 6 u + 4 u
= 19 u
= 19 x 39
= 741
Answer(s): 741