Hartley opened a food truck business to sell food on the street. On day 2 he earned $112 and on day 5 he earned $367. At this rate, how much will Hartley earn on day 10?

I know the answer is $792 but can someone please explain? The explanation I have doesn't seem to make sense to me.

Question

Hartley opened a food truck business to sell food on the street. On day 2 he earned $112 and on day 5 he earned $367. At this rate, how much will Hartley earn on day 10? 

I know the answer is $792 but can someone please explain? The explanation I have doesn't seem to make sense to me.

anonymous · Answer

Calculate rate of earning per day. So he earns $(367-112) in 5-2 days, i.e $255 in 3 days.So $85 per day.For 10 days earning, on day 5 he earns $367 and in the next five days he will earn $85*5 = 425. So, total earning  = $367+$425 = $792.