Question

find out the solution for this question for both questions

Answer 1

given: x to y, speed = 72 km/h
           y to x , speed = 63km/h

let the distance x to y be called xy.

let time taken to go from x to y be t1 and that of y to x be t2.
we know that, t= d/s    (t =time, d = distance and s = speed)

t1 = xy/72

t2 = xy/63
so t1 + t2 = xy/72 + xy/63

you'll get t1 + t2 = (63xy+72xy)/72*63

average speed = total distance / total time taken
or, Vavg = 2xy/[ (63xy+72xy)/72*63 )]
therefore, Vavg = 2*72*63/135
therefore average speed for the whole journey is 67.2 m/s

for 2nd question sry I haven't revised statistics, srry!!!:(