Question

Two cars A and B race each other. The Car A ran for 2 minute at a speed of 7.5 km/h, slept for 56 minute and again ran for 2 minute at a speed of 7.5 km/h. find the average speed of the car A in the race.​

Answer 1

Answer:

Explanation:

Average Speed = Total distance/ total time

s1 = 7.5 km/h = 25/12 m/s

t1 = 2 min = 120 second

speed = distance/time , distance = speed × time

distance1 = 25/12 × 120 = 250 m

Slept for 56 min = 56 × 60 second = 3360 second

s2 = 7.5 km/h = 25/12 m/s

t2 = 2 min = 120 second

distance2 = 25/12 × 120 = 250 m

Average Speed = Total distance/ total time

Avg speed = (d1 + d2)/Total time

Avg speed = (250 + 250) / 120 + 3360 + 120 m/s

Avg speed = 500 / 3600 m/s

Avg speed = 5/36 m/s = 1/2 km/h = 1/120 km/min

Answer 2

Gíven:

• Two cars A and B race each other. The Car A ran for 2 minute at a speed of 7.5 km/h, slept for 56 minute and again ran for 2 minute at a speed of 7.5 km/h.

To Fínd:

• Find the average speed of the car A in the race.?

Formula Used:

$\\ \bullet \: \: \: \underbrace{\sf\large\blue{ Distance = Speed \times Time }}$

Solutíon:

Distance = Speed × Time

Distance travelled in first 2 minute = ${\sf{ \dfrac{7.5 \times \cancel{2}}{ \cancel{60}^{ \: \: 30 }} = 0.25km }}$

Distance travelled in last 2 minute = ${\sf{ \dfrac{7.5 \times \cancel{2}}{ \cancel{60}^{ \: \: 30 \: }} = 0.25km }}$

Total distance = 0.25 + 0.25 = 0.5 km

Total time = 2 + 2 + 56 = 60 minute = 1 hr

Average speed = ${\sf\green{ \dfrac{0.5}{1} }}$

$\implies{\sf{ 0.5 \: km/hr}}$

Therefore,

The average speed of the car A in the race is 0.5 km/hr.