In a school, the ratio of adults to the number of children is 5 : 6.
The ratio of the number of girls to the number of boys is 3 : 1.
There are 78 less boys than girls.
How many people are there in the school?
Adults |
Children |
5 x 2 |
6 x 2 |
|
Girls |
Boys |
|
3 x 3 |
1 x 3 |
10 u |
9 u |
3 u |
The number of children is the combined repeated identity.
Make the number of children the same using the LCM of 6 and 4.
LCM of 6 and 4 = 12
Number of less boys than girls
= 9 u - 3 u
= 6 u
6 u = 78
1 u = 78 ÷ 6 = 13
Number of people
= 10 u + 9 u + 3 u
= 22 u
= 22 x 13
= 286
Answer(s): 286