Candidates of four schools appear in a mathematics test. The data were as follows:

Schools	Number of candidates	Average score
I	60	75
II	48	80
III	Not available	55
IV	40	50

If the average score of the candidates of all the four schools is 66

Given:

The average score of the candidates of all the four schools is 66.

To do:

We have to find the number of candidates that appeared from school III.

Solution:

Let the number of candidates that appeared from school III be $p$.

Therefore,

 We know that,

Mean$=\frac{\sum fx}{\sum f}$

Therefore,

Mean $66=\frac{10340+55p}{148+p}$

$66(148+p)=10340+55p$

$9768+66p=10340+55p$

$66p-55p=10340-9768$

$11p=572$

$p=\frac{572}{11}$

$p=52$

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Updated on: 10-Oct-2022

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