A car takes 15 minutes less to cover a distance of 75 km, if it incre…

Question

A car takes 15 minutes less to cover a distance of 75 km, if it increases its speed by 10 km/hr from its usual speed. How much time would it take to cover a distance of 300 km using this speed ?

Accepted Answer

Option A. 5 hrs. Answer & Solution Answer: Option A Solution: Let the usual speed be x km/hr Then, & 75x - 75x + 10 = 1560 & x ( x + 10 ) = 3000 & x^2 + 10x - 3000 = 0 & ( x + 60 ) ( x - 50 ) = 0 & x = 50 ∴ Required time : & = ( 30060 ) hrs & = 5 hrs