Question

Of the 84 parents who attended a meeting at a school, 35 volunteered to supervise children during the school picnic and 11 volunteered both to supervise children during the picnic and to bring refreshments to the picnic. If the number of parents who volunteered to bring refreshments was 1.5 times the number of parents who neither volunteered to supervise children during the picnic nor volunteered to bring refreshments, how many of the parents volunteered to bring refreshments

Answer 1

The number of parents who volunteered to bring refreshments is 16.

Explanation:

The information provided is:

N = 84

n (S) = 35

n (S ∩ R) = 11

n (R) = 1.5 × n (S' ∪ R')

Compute the value of n (S ∪ R) as follows:

`n(S\cup R)=n(S)+n(R)-n (S\cap R)\\\\n(S\cup R)=n(S)+[1.5(N-n(S\cup R)]-n (S\cap R)\\\\n(S\cup R)=n(S)+1.5N-1.5n(S\cup R)-n (S\cap R)\\\\2.5n(S\cup R)=n(S)+1.5N-n (S\cap R)\\\\2.5n(S\cup R)=35+(1.5*84)-11\\\\2.5n(S\cup R)=150\\\\n(S\cup R)=(150)/(2.5)\\\\n(S\cup R)=60`

Now compute the value of n (R) as follows:

`n (R) = 1.5 * n (S' \cup R') \\\\n (R) = 1.5 * [N-n (S \cup R)]\\\\n (R) = 1.5 * [84-60]\\\\n(R)=16`

Thus, the number of parents who volunteered to bring refreshments is 16.