a cheetah can run

Question

A cheetah can run 20 miles per hour faster than a lion. A cheetah can run seven miles in the same time that a lion can run 5 miles. Find the speed of each animal. 

Answer 1

let C = speed of cheetah; let  L = speed of lion --- then C = L + 20 --- also, from distance = speed (time), we have time = distance/speed --- so that, 7/C = 5/L --- or C =(7/5)L --- then, (7/5)L = L + 20 --- or, (2/5)L = 20 --- or, L = (5/2)20 --- or, L = 50 --- and C = L + 20 = 50 + 20 = 70