Question

A distance of $33$ km is covered in one hour $12$ minutes . If the first $15$ km is covered at the speed of $25$ km per hour , find the speed during the remaining distance .

• A. $35$ km/hr
• B. $20$ km/hr
• C. $30$ km/hr
• D. $15$ km/hr

Answer 1

Answer: (C)

$30$ km/hr

$speed=\frac{distance}{time}$

$distance=33km$

$time=1hr12min=1+\frac{1\times 12}{60}=1.2hrs$

Now, the first 15 km is covered at the speed of 25 km/hr

Therefore,

$distance=15km$

$speed=25km/hr$

$\Rightarrow 25=\frac{15}{time}$

$\Rightarrow time=\frac{15}{25}=0.6hr$

Now, the time left is $(1.2-0.6=0.6hr)$ and the distance left is $(33-15=18km)$

Therefore,

$\Rightarrow speed=\frac{18}{0.6}km/hr$

$\Rightarrow speed=30km/hr$