Derek is training for a half-marathon. His training plan sets his goal for this week at 18 miles with three short runs and one longer run.

His three short runs total 9.35 miles.

How long will his long run need to be to meet his goal?

8.65 miles

Step-by-step explanation:

The total of his short runs are 9.35 so you need to find out how many miles he has left till he reaches 18 miles.

The equation you can use is 9.35 + x = 18 x will equal the number of miles for the long run.

9.35 + x = 18

to isolate x you will subtract 9.35 from both sides.

you will get:

x = 8.65

8.65 miles