How can we write the sum of 13 and 17 quadrupled as a numerical expression

How do i multiply two digit numbers

The product of 3 and a number increased by 8 is 31 written as an equation

Martha is training for a duathlon, which includes biking and running. she knows that yesterday she covered a total distance of over 55.5 miles in more than than 4.5 hours of training. martha runs at a speed of 6 mph and bikes at a rate of 15.5 mph.