# A man cycles from home to work at 15 km/h and returns at 20 km/h. If the next day he increases the speed of going by 5% and decreases the speed of coming by 10%, what is his average speed.

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### 2 Answers

The man cycles from home to work at 15 km/h and returns at 20 km/h.

If the speed of going is increased by 5% an the speed at which he returns is decreased by 10%, the respective speeds are 15*(1+0.05) = 15.75 km/ h and 20*(1 - 0.1) = 18 km/h.

**The average speed is now (15.75 + 18)/2 = 16.875 km/h**

Going to work km/h Coming to home km/h Average km/h

15 20 15*20/2= 17.5

Next day increases 5% decreases by 10%

15+(15*5/100) 20-(20*10/100)

15+.75 20-2

15.75 18 15.75*18/2= 16.875