i cant figure out the equation and dont know what to do

Question

Ben ran and biked for a total of 72 minutes. Ben runs a mile in 10 minutes but bikes a mile in 4 minutes. He biked twice as far as he ran.  what are the equations to the system and the answer

Answer 1

He runs 4 miles in 40 minutes (4x10)

He bikes 8 miles in 32 minutes (8x4)

40 +32 =72 minutes to go 12 miles

that's an average 12/72 = 1/6 miles per minute

in 72 minutes that's 72(1/6) = 12 miles

He runs 1 mile in 10 minutes. in 40 minutes, that's 4 miles

He bikes 1 mile in 4 minutes, in 32 minutes that's 8 miles