A jogger ran 3 ​miles, decreased her speed by 1 mile per​ hour, and then ran another 4 miles. If her total jogging time was 1 2/21 ​hours, find her speed for each part of her run.

Question

A jogger ran 3 ​miles, decreased her speed by 1 mile per​ hour, and then ran another

4 miles. If her total jogging time was

1 2/21 ​hours, find her speed for each part of her run.

Answer 1

Let s =speed on the first part of her run. Let t₁ = time taken for 1st part of run & t₂ time for 2nd part of run.

The total distance run was 7 hours and the total time taken was 12/21 hours . Recall speed times time equals distance. We have the equation:

s ( t₁ + t₂ ) = 7 or s x 12/21 = 7 Solving for s we get s = 4 miles per hour on 1st leg of her run and

s - 1 =3 miles per hour on second leg of her run

Answer 2

Let s =speed on the first part of her run. Let t₁ = time taken for 1st part of run & t₂ time for 2nd part of run.

The total distance run was 7 hours and the total time taken was 12/21 hours . Recall speed times time equals distance. We have the equation:

s ( t₁ + t₂ ) = 7 or s x 12/21 = 7 Solving for s we get s = 4 miles per hour on 1st leg of her run and

s - 1 =3 miles per hour on second leg of her run