Answer:
120 +10w = 75 + 15w, w=weeks, found by adding savings to rate times and unknown variable of weeks and setting equal to each other. 9 wks, $210
Step-by-step explanation:
120 +10w = 75 + 15w
120-75= - 10w+15w
45=5w
45/5=9
9 weeks
120 + 90 = 75 + 135
210= 210