In a school, the ratio of adults to the number of children is 3 : 1.
The ratio of the number of boys to the number of girls is 7 : 2.
There are 10 less girls than boys.
How many people are there in the school?
Adults |
Children |
3 x 9 |
1 x 9 |
|
Boys |
Girls |
|
7 x 1 |
2 x 1 |
27 u |
7 u |
2 u |
The number of children is the combined repeated identity.
Make the number of children the same using the LCM of 1 and 9.
LCM of 1 and 9 = 9
Number of less girls than boys
= 7 u - 2 u
= 5 u
5 u = 10
1 u = 10 ÷ 5 = 2
Number of people
= 27 u + 7 u + 2 u
= 36 u
= 36 x 2
= 72
Answer(s): 72