we have that
the linear equation that represent this situation is equal to
E=15h
so
1) H=15=E -------> false
2) If Caroline ...... for 5 hours , she earns $20 ------> false
because she earns E=15(5)=$75
3) If E=52.50
solve for h
E=15h
52.50=15h
h=52.50/15
h=3.5 or h=3 1/2 hours
statement is true
4) statement is true
because
E=15h
h=5f
E=75f