The length of the boston marathon is 138,435 ft. each stride, or step, by a particular runner is 3 ft long. does the number of strides the runner takes fit evenly into the length of the race? explain

Yes! If you divide 138,435 by 3, the number of strides the runner takes fit evenly into the length of the race. Therefore the answer is 46,145 ft.

Fit evenly basically means does the runner need to take a whole number of steps to complete the race, assuming the runner travels a consistient distance per stride

easy way is
is 138435 divisble by 3?
a hack to tell if a number is divisble by 3 is to add the digits and if the sum is divisble by 3, it is divisble
1+3+8+4+3+5=24
24 is 3 times 8

it is divisible by 3
yes

The first option would be correct if it were one half and not one