Question

15. At a school fair, 70% of the people are under 16 years old. One of the people

teachers. If there are 21 teachers at the fait, how many people are there at the air

Answer 1

210 people.

Explanation:

Here is the correct question: At a school fair, 70% of the people are under 16 years old. One third of the people remaining are teachers. If there are 21 teachers at the fair, how many people are there at the fair?

Now, solving to find total number people in the fair.

Lets assume total number of people in the fair is "x".

As given, there is 70% of total number of people are under 16 year old.

∴ People under 16 year old=
`70\% of x= (7x)/(10)`

Next, finding the number of remaining people.

∴ Number of remaining people=
`x-(7x)/(10) = x-0.7x`

Number of remaining people is 0.3x

As given, One third of the people remaining are teachers.

∴ Number of teachers=
`(1)/(3) * 0.3x= 0.1x`

As given there are 21 teachers at the fair.

⇒
`0.1x= 21\ teachers`

∴ x=
`(21)/(0.1) = 210`

Hence, total number of people in the fair are 210.