Question

Gasoline mileage of a car is 40 mph. On a smooth road, it’s milage is 5% higher. What is it’s milea on a smooth road?

Answer 1

Mileage would be 42 mph

Answer 2

It helps to think of a simpler problem. Let's say mpg is 20 and 10% higher on a smooth road.

How many miles will you get with one gallon on a regular road?

How many more miles will you get on a smooth road? 10% more, right? How much is that?

OK - so you've now solved a simpler problem. Use the exact some process to solve your, more complicated, problem.