Question

A bus travels the first one third distance at a speed of ,10ms the next one third distance at 20ms and remaining one-third at 40 ms. The average speed of the bus for the whole journey is:​

Answer 1

Answer:

$\bigstar{\bold{Average\;speed=17.14\:m/s}}$

Explanation:

$\Large{\underline{\sf{Given:}}}$

• Bus travels first one third distance at a speed of 10 m/s
• The next one third it travels at a speed of 20 m/s
• The last one third at a speed of 40 m/s

$\Large{\underline{\sf{To\:Find:}}}$

• Average speed for the whole journey

$\Large{\underline{\sf{Solution:}}}$

➛ First we have to find the total distance covered by the bus

➛ Let the bus travel x m in each of the three cases

➛ Total distance travelled = x + x + x

    Total distance travelled = 3x m

➛ Now we have to find the time taken in each of the three cases.

➛ We know that,

    Time = Distance/Speed

➛ In the first case,

   Time = x/10 s

➛ In the second case,

   Time = x/20 s

➛ In the third case,

    Time = x/40 s

➛ Hence,

   Total time taken = x/10 + x/20 + x/40

   Total time taken = 4x/40 + 2x/40 + x/40

   Total time taken = 7x/40 s

➛ Now average speed of the bus is given by,

   Average speed = Total distance travelled/Total time taken

   Average speed = 3x ÷ 7x/40

   Average speed = 3 × 40/7

   Average speed = 17.14 m/s

➛ Hence average speed of the bus is 17.14 m/s.

   $\boxed{\bold{Average\;speed=17.14\:m/s}}$