Book Online Demo

Check Your IQ

Try Test

Courses

Dropper NEET Course Dropper JEE Course Class - 12 NEET Course Class - 12 JEE Course Class - 11 NEET Course Class - 11 JEE Course Class - 10 Foundation NEET Course Class - 10 Foundation JEE Course Class - 10 CBSE Course Class - 9 Foundation NEET Course Class - 9 Foundation JEE Course Class -9 CBSE Course Class - 8 CBSE Course Class - 7 CBSE Course Class - 6 CBSE Course

Offline Centres

A bus is travelling the first one third distance at a speed of $10 km / h$ the next one fourth of the total distance at $20 km / h$ and remaining at $40 km / h$ . What is the average speed of the bus?

see full answer

High-Paying Jobs That Even AI Can’t Replace — Through JEE/NEET

🎯 Hear from the experts why preparing for JEE/NEET today sets you up for future-proof, high-income careers tomorrow.

An Intiative by Sri Chaitanya

17.78 km / h

28.24 km / h

18 km / h

20 km / h

answer is A.

(Unlock A.I Detailed Solution for FREE)

Best Courses for You

JEE

NEET

Foundation JEE

Foundation NEET

CBSE

Detailed Solution

A bus is travelling the first one third distance at a speed of

10 km / h

the next one fourth of the total distance at

20 km / h

and remaining at

40 km / h

, the average speed of the bus

17.78 km / h

.
Let total distance be

D km

.
One third distance will be

D / 3 km

and time will be

\frac{D}{30} h

.
For next one fourth

(D / 4)

of the total distance’s time will be

\frac{D}{80} h

.
And remaining

5 D / 12

40 km / h

, So time will be

\frac{5 D}{480} h

.
So total time will be,

\frac{D}{30} + \frac{D}{80} + \frac{5 D}{480} = \frac{27 D}{480}

As we know

average speed = \frac{Total distance}{Total time}

so average speed

= \frac{D}{(\frac{27 D}{480})}

= \frac{480}{27}

= 17.78 km / h

Watch 3-min video & get full concept clarity

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Online Course for IIT JEE

Best Online Course for NEET

Best Online Course for CBSE

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Get Expert Academic Guidance – Connect with a Counselor Today!