In a school, the ratio of children to the number of adults is 10 : 7.
The ratio of the number of men to the number of women is 5 : 2.
There are 30 less women than men.
How many people are there in the school?
Children |
Adults |
10 x 1 |
7 x 1 |
|
Men |
Women |
|
5 x 1 |
2 x 1 |
10 u |
5 u |
2 u |
The number of adults is the combined repeated identity.
Make the number of adults the same using the LCM of 7 and 7.
LCM of 7 and 7 = 7
Number of less women than men
= 5 u - 2 u
= 3 u
3 u = 30
1 u = 30 ÷ 3 = 10
Number of people
= 10 u + 5 u + 2 u
= 17 u
= 17 x 10
= 170
Answer(s): 170