shubhangi wrote:

instead of such a long procedure .. there's a shortcut..

u know it takes x hours to travel A-B and return in twice as fast so u will cover return journey in half the time u spend while goin.. so x/2 ..add both x+x/2= 3x/2..

yes. this is the most intuitive way to solve it rather than get boggled down in formulas and pluggin in "smart numbers"

here is the "smart number" way

R*T=D

let t=x

let d= 8 ("smart number")

going from A to B

R*T=D

R*x=8

plug in another smart number for x (x=4)
R*4=8

R=2

on the way back from B to A

R*T=D

R*?=8

4*?=8 (twice as fast)

T=2

therefore, 4+2=6 hours total

we originally set x=4

therefore, 6 = 3/2x