Jack needs to save $125 to go to a concert. he has saved $35. he makes $7.50 an hour at his job. which equation and solution can be used to show how many hours jack must work in order to have enough money to go to the concert?

a.)125x + 35 = 750; x = 5.75

b.) 35x + 125 = 750; x = 18

c.)35−7.5x=125; x=6

d.)7.5x + 35 = 125; x = 12