Starting at home, ishaan traveled uphill to the gift store for 18 minutes at just 10 mph. he then traveled back home along the same path downhill at a speed of 30 mph. what is his average speed for the entire trip from home to the gift store and back?

"18 minutes at just 10 mph"

18/60 = 0.3

18 minutes = 0.3 hour

0.3 hour * 10 mph = 3 miles

The distance uphill was 3 miles traveled in 0.3 hour.

The trip downhill is the same distance, 3 miles. He traveled it at 30 mph.

(3 miles)/(30 mph) = 0.1 hour

0.1 * 60 = 6

The trip back was 3 miles in 6 minutes.

The total distance (to the store and back) was 3 miles + 3 miles = 6 miles.

The total time was 18 minutes + 6 minutes = 24 minutes = 24/60 hour = 0.4 hour

Speed = distance/time = (6 miles)/(0.4 hour) = 15 mph

15 mph