Question

a child goes around a equilatral triangle park from a to b 10 km per hour and b to c 12 km per hour and c to a 15 km per hour what
is his average speed ​

Answer 1

Answer:12.86 km per hour

Step-by-step explanation:

Let the side of the equilateral triangle = l km

The time taken to travel l km @ 10 km/h= l/10 h

The time taken to travel lkm@12 km/h= l/12 h

The time taken to travel l km@20 km)h= l/20 h

Total time taken to travel 3l km = l[( 1/10)+(1/12)+(1/20)] h= l[(6+5+3)/60]= 14 l /60 h

Average speed= total distance covered ÷ total time taken= (3 l) ÷ 14l/60=3× 60/14 = (90/7) km per hour=12.857 km per hour= 12.86 km per hour