Respuesta :
They need to wash a total of 15 + 113 = 128 cars.
James washes 17 cars per hour.
Lily washes 12 cars in 3 hours: 12 / 3 = 4 cars per hour.
Harry washes 13 cars in 2 hours: 13 / 2 = 6.5 cars per hour.
17 + 4 + 6.5 = 27.5 cars per hour total.
128 cars / 27.5 cars per hour = 4.65 hours total.
The answer is C.