I can't figure this question out

Question

today,joelle walked 20 minutes at a rate of 3miles per hour,and she ran 15 minutes at a rate of 6 miles per hour. how many total miles did joelle travel while walking and running

Answer 1

Here's what we know:

D = r * t (Distance equals rate * time)

D₁ = ^{3 mi}/_hr * ^{1 hr}/₃ (the 1st section she walked for 20 min (1/3 of an hour) at a rate of 3 miles an hour)

D₂ = ^{6 mi}/_hr * ^{1 hr}/₄ (the 2nd section she ran for 15 min (1/4 of an hour) at a rate of 6 miles an hour)

 

Solve D₁ and D₂, and then add them together for your final answer.