Step-by-step explanation: he gets 70.40$ to work for 4 hours so you'll have to multiply 4 by 70.40 to represent it's doubling to 8 and you'll get 281.60
70.40x4=281.60
so add this 4 to the other 4 it makes 8 because that's how much it would take to get there 4 steps up to really =8