In a school, the ratio of adults to the number of children is 5 : 7.
The ratio of the number of girls to the number of boys is 7 : 1.
There are 84 less boys than girls.
How many people are there in the school?
Adults |
Children |
5 x 8 |
7 x 8 |
|
Girls |
Boys |
|
7 x 7 |
1 x 7 |
40 u |
49 u |
7 u |
The number of children is the combined repeated identity.
Make the number of children the same using the LCM of 7 and 8.
LCM of 7 and 8 = 56
Number of less boys than girls
= 49 u - 7 u
= 42 u
42 u = 84
1 u = 84 ÷ 42 = 2
Number of people
= 40 u + 49 u + 7 u
= 96 u
= 96 x 2
= 192
Answer(s): 192