C = total rental cost, m = # of miles you drive, w = # of week you rent
Place #1
C = $10 per week * number weeks + $0.29 per mile * number of miles
C = 10w + 0.29m
Place #2
C = $0.35 per mile * number of miles
C = 0.35m
You’re told you’ll rent it for 3 week, so m=3.
Place #1: C = 10*3 + 0.10m
Place #2: C = 0.35m
Both agencies “charge the same” means the costs are the same. So set the two equations equal and solve for m.