Question

Abdul, while driving to school, computes the average speed for his trip to be 60 kmh-1. On his return trip along the same route, there is less traffic and the average speed is 40 kmh-1. What is the average speed of Abdul’s trip? 

2 points

24 km/h

40 km/h

50 km /h

48km/h

please answer​

Answer 1

$\huge \mathfrak{ \underline{ \color{lime}{Solution} }}$

Let us assume that Abdul is traveling x kilometer distance while going to school Distance = Speed ×Time.

1) When it’s Average speed is 20km/h

$\sf{x = v_1 × t_1 = 20 × t_1}$

2) When it’s Average speed speed is 30km/h

$\sf{x = v_2 × t_2 × = 30 × t_2}$

$\sf{V_{average} =\frac{ total \: distance \: traveled }{ total \: time \: taken } }$

$\sf{V_{average} = \frac{x + x}{ \frac{x}{ v_1 } + \frac{x}{v_2} } = \frac{2x}{ \frac{x}{20} + \frac{x}{30}} = 24km/h}$

Hence, Average strip of Abdul’s strip = 24km/h