Okay so because we are talking about the rate of km per hour. This means that car A is going 208km per hour. We are trying to find out how many km at 12 hours so we are going to multiply: 208x12= 2496km Now we have to do the same for car B: 215x12= 2580km Next we have to figure out how many km more did car B drive than car A so we have to subtract: 2580-2496= 84km Hope this helps(;