Question

Ei) A car travels at a speed of 50 km/hr for 30
minutes, at 30 km/hr for next 15 minutes
and then 70 km/hr for next 45 minutes.
What is the average speed of the car?​

Answer 1

Answer:

GIVEN:

• S = 50 km/hr
• t = 30 minutes
• S' = 30 km/hr
• t' = 15 minutes
• S"= 70 km/hr
• t" = 45 minutes

Solution:

$\large\bold{\boxed{\boxed {Average\:speed\:=\:\frac{total\:distance}{total\:time\:taken} }}}]$

D = speed x time

D = 50 x 0.5

= 25 km

D' = 30 x 0.25

= 7.5km

D"= 75 x 0.75

= 52.5km

Therefore average speed = $\large\bold{ \frac{total\:distance }{total\:time} }$

= $\large\bold{ \frac{D\:+\:</p><p>D'\:+\:D" }{t\:+\:t'\:+\:t"} }$

=$\large\bold{ \frac{25\:+\:</p><p>7.5\:+\:52.5}{0.5\:+\:0.25\:+\:0.75} }$

=$\large\bold{ \frac{85}{1.5} }$

$\large\bold{\boxed{\boxed{Average\:speed\:=\:56.67\:km/hr}}}$