A body moving at 2m/s can be stopped over a distance x. If its kinetic energy is doubled, how long will it go before coming to rest, if the retarding force remains unchanged

Q : A body moving at 2m/s can be stopped over a distance x. If its kinetic energy is doubled, how long will it go before coming to rest, if the retarding force remains unchanged
(A) x
(B) 2x
(C) 4x
(D) 8x

Solution : If R = resistance
Rx₁ =ΔKE₁ = KE . .. (i)
Rx₂ = ΔKE₂ =2KE . . . (ii)
Dividing (ii) by (i) 
 x₂ = 2x₁ = 2x