You're answer is the third one, you gotta divide the money by the hours worked and then compare.
( 12 + 7) 5x = 95 so that's your answer
5n+ 5= 17
5n= 17-5
5n= 12
N= 12/5
N= 2.4
The answer is 2.4.
Hope this helps!
N= Heidi's marbles
92 - n =18 (Barry's 92 marbles - whatever Heidi has = 18 marbles difference)
92 -n +n = 18 +n (I added n to each side)
92 = 18+n
92 -18 = 18-18 + n (I subtracted 18 from both sides)
74 = n Heidi has 74 marbles
