Which model does the graph represents?

Some boys and girls were asked if they had a pet. one third of the group were boys. there were 20 boys. 20% of the girls had a pet. boys with a pet : girls with a pet = 1 : 5 i need to know how many girls there are.

What is the effect on the graph of the function f(x)=x when f(x) is replaced with -f(x)+4

Sally deposited money into a savings account paying 4% simple interest per year.the first year,she earned $75 in interest.how much interest will she earn during the following year?