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?

The distance to the store is
.. (0.3 h)*(10 mi/h) = 3 mi

The time home is
.. (3 mi)/(30 mi/h) = 0.1 h

The average speed is the total distance divided by the total time
.. speed = (3 mi +3 mi)/(0.3 h +0.1 h) = (6 mi)/(0.4 h) = 15 mi/h

Ishaan's average speed was 15 mi/h.