A chopper flies along the four sides of a square at the speeds of 100,200,300 and 400 km/hr. Find the average speed of the plane around the field?  Choose the correct choice from the following choices.
A) 100km/hr B) 192km/hr C) 154km/hr D) 212km/hr E) 168km/hr
Let each side of the square be x   Let the average speed of the chopper be y km/hr   x/100 + x/200 + x/300 + x/400 = 4x/y   25x/1200 = 4x/y   y = 1200*4/25= 
<gadget id="calculator">1200*4/25</gadget>
<output>192</output>
192km/hr   Answer is 192km/hr
<result>B</result>
A chopper flies along the four sides of a square at the speeds of 100,200,300 and 400 km/hr. Find the average speed of the plane around the field?