A car moves a distance of 200 m.It covers the first half of the distance at speed 40 km/h and the second half of distance at speed v. The average speed is 48 km/h. The value of v is

Question

A car moves a distance of 200 m.It covers the first half of the distance at speed 40 km/h and the second half of distance at speed v. The average speed is 48 km/h. The value of v is (A) 56 km/h (B) 60 km/h (C) 50 km/h (D) 48 km/h

Tardigrade Admin · Accepted Answer

Given, Distance =200 m, Speed =40 km / h Average speed =48 km / h 48=(200/(100)40+(100) v ⇒ (1/40)+(1/ v )=(1/24) ⇒ v =(120/5-3)=(120/2) ⇒=60 km / h

Q. A car moves a distance of $200 m .$ It covers the first half of the distance at speed $40 km / h$ and the second half of distance at speed v. The average speed is $48 km / h$ . The value of $v$ is

56 km/h

60 km/h

50 km/h

48 km/h

Given, Distance $= 200 m$ , Speed $= 40 km / h$ Average speed $= 48 km / h$
$48 = \frac{200}{\frac{100}{40} + \frac{100}{v}}$
$\Rightarrow \frac{1}{40} + \frac{1}{v} = \frac{1}{24}$
$\Rightarrow v = \frac{120}{5 - 3} = \frac{120}{2}$
$\Rightarrow= 60 km / h$

Q. A car moves a distance of 200m.It covers the first half of the distance at speed 40km/h and the second half of distance at speed v. The average speed is 48km/h. The value of v is