What does at most in inequality mean

Ernest is purchasing a $175,000 home with a 30-year mortgage. he will make a $15,000 down payment. use the table below to find his monthly pmi payment.

In a two-digit number the units' digit is 7 more than the tens' digit. the number with digits reversed is three times as large as the sum of the original number and the two digits. find the number.

Arectangular garden is 5 feet long and 3 feet wide. a second rectangular garden has dimensions that are double the dimensions of the first garden. what is the percent of change in perimeter from the first garden to the second garden?