A car covers the first half the distance between two places at 40 km/h another half at 60 km/h, the average speed of car

Question

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Answer 1

Letx consider, $x =$ total distance covered by the car,
Time taken to complete the half distance with velocity $v = 40 k m / h$ ,
$t_{1} = \frac{x}{2 \times 4 0} = \frac{x}{8 0} h r$ . . . . .(1)
The time taken to complete another half distance with velocity $u = 60 k m / h$
$t_{2} = \frac{x}{2 \times 6 0} = \frac{x}{1 2 0} h r$
The total time taken, $t = t_{1} + t_{2}$
$t = \frac{x}{8 0} + \frac{x}{1 2 0} = \frac{x}{4 8} h r$
The average speed of the car,
$v_{a v g} = \frac{x}{x / 4 8} = 48 k m / h$
The correct option is B.

Answer 2

Letx consider,

x =

total distance covered by the car,

Time taken to complete the half distance with velocity

v = 40 k m / h

,

t_{1} = \frac{x}{2 \times 4 0} = \frac{x}{8 0} h r

. . . . .(1)

The time taken to complete another half distance with velocity

u = 60 k m / h

t_{2} = \frac{x}{2 \times 6 0} = \frac{x}{1 2 0} h r

The total time taken,

t = t_{1} + t_{2}

t = \frac{x}{8 0} + \frac{x}{1 2 0} = \frac{x}{4 8} h r

The average speed of the car,

v_{a v g} = \frac{x}{x / 4 8} = 48 k m / h

The correct option is B.