Question

SEE QUESTION IN IMAGE

Answer 1

Explanation:

`Mean=(all.ages.added.together.of.all.kids)/(total.number.of.kids)` Hopefully, that makes sense! To get the numerator of that problem, we take the number of kids and multiply it by the corresponding age and add them all together. To get the denominator, we add the total number of kids together. That will look like this mathematically, setting the mean equal to 14.44, as stated:

`14.44=(13(15)+14(42)+15X+16(10)+17(3))/(15+42+X+10+3)` and simplify that a bit to

`14.44=(195+588+15X+160+51)/(70+X)` and a bit more to

`14.44=(994+15X)/(70+X)` and cross multiply

14.44(70 + X) = 994 + 15X and

1010.8 + 14.44X = 994 + 15X and

16.8 = .56X so

X = 30

30 kids are 15 years old for the mean age to be 14.44

Answer 2

d.30

Answer:

Solution given:

x.
`\:\:\:` f.
`\:\:\:` fx

13.
`\:\:\:` 15.
`\:\:\:` 195

14.
`\:\:\:` 42
`\:\:\:` 588

15.
`\:\:\:` x.
`\:\:\:` 15x

16.
`\:\:\:` 10.
`\:\:\:` 160

17.
`\:\:\:` 3.
`\:\:\:` 51

. n=70+x.
`\sum`=994+15x

we have

mean=sum/n

14.44=
`\bold{(\sum)/(n)}`

14.44=
`\bold{(994+15x)/(70+x)}`

doing crisscrossed multiplication

(70+x)*14.44=994+15x

1010.8+14.44x=994+15x

15x-14.44x=1010.8-994

0.56x=16.8

x=16.8/0.56

x=30