The answer is 38, because if you take away the 15 he bought afterwards (34-15) you get 19, and then since he sold half his collection you would double that (19×2) and that's 38.
F(x)=95x written as a function of x
Answer: mean=87, median=87.5 and range=18
Step-by-step explanation:
Mean:
First add all the numbers
78+95+77+92+87+79+94+86+88+94 = 870
Then you divide the answer by counting the numbers
870÷10
=87
Median:
First arrange the numbers in ascending order (from smallest to largest)
77, 78, 79, 86, 87, 88, 92, 94, 94, 95
pick the two middle numbers which is 87 and 88
then you do 
= 175÷2
= 87.5
range = Largest number - smallest number
= 95-77
= 18

First I found the number of adults by multiplying .60 by 700. It was 420. From there all I had to do was subtract it from 700. Revealing the number of children to be 280.