Mark runs 5 miles in 40 minutes. Of he continues at the rate, how many miles will he run in 160 miles

The answer would be 20 miles. Do a proportion, 5/40 = x/160. Cross multiply and divide. 5 x 160 = 800, 800 divided by 40 = 20. Now you can also look at it like this 5 miles = 40 minutes. This means every 40 minutes they have done 5 miles. 40 goes into 160 four times. 5 x 4 = 20