He can expect $25 because if you use the properties of proportions for each time were $5. They are the $15 of the last month. So, that month he will have $25.
his dad paid him 15 dollars to mow the lawn three times. from this we know he gets paid 5 dollars for every time he mows. if he mows five times, he should expect 25 dollars because 5 times five is 25.
