What number produces an itrational number when multiplied by 1/3

Find the solution of each of the following.

Mikes car gets an average of 28 mpg. there are 12 gallons of fuel in mikes car when he starts his trip of 140 miles. about how many gallons are left at the end of his trip?

Ebert used to make $22 an hour, but got a 10% raise. how much more will he make in a 40 hour work week with raise?