Candidates of four schools appear in a mathematics test. The data were as follows School, No. of Candidates, Average Score I II III IV, 60 48 Not available 40, 75 80 55 50 If the average score of the candidates of all the four schools is 66, find the number of candidates that appeared from school III.

Explanation

Let the number of candidates that appeared from school lll be `x`

Given:Mean =`66`
`Mean=(sum_"fixi")/(sum_"fi")`
`66=(10340+55x)/(148+x)`
`66(148+x)=10340+55x`
`9768+66x=10340+55x`
`66x-55x=10340-9768`
`11x=572`
`therefore x=572/11=52`
`therefore
" the Number of candidates from school lll is" 52`