Maths-
General
Easy

Question

In the first half of the journey a bus travelled with an average speed of 20 km/hr. If the given average speed for the complete trip made by the bus is 24 km/hr, then calculate the average speed covered by the bus in the second half of the trip.

Hint:

Let the distance of entire journey is D
Distance in half journey = D/2
Let the time taken by bus to cover the 2nd half of the journey be x kmph .
By using Time = (distance )/ Avg. speed
Find the total time ,and time covered in 1st half and time covered in 2nd half
We know total time = time covered in 1st half + time covered in 2nd half

The correct answer is: 30kmph.


    Ans :-  The average speed covered by bus in the second half of the journey = 30kmph.
    Explanation :-
    Avg. Speed in 1 st half of journey is 20kmph
    Avg. Speed in entire journey is 24 Kmph
    Let the time taken by bus to cover the 2nd half of the journey be x kmph .
    Step 1:- Find the total time ,and time covered in 1st half and time covered in 2nd half.
    T o t a l space t i m e space t a k e n space equals space left parenthesis t o t a l space d i s tan c e space o f space e n t i r e space j o u r n e y space right parenthesis divided by left parenthesis A v g. s p e e d space o f space e n t i r e space j o u r n e y right parenthesis
    T o t a l space t i m e space t a k e n spaceD over 24
    t i m e space t a k e n space i n space 1 s t space h a l f equals left parenthesis d i s tan c e space o f space 1 s t space h a l f space j o u r n e y space right parenthesis divided by left parenthesis A v g. s p e e d space o f space 1 s t space j o u r n e y right parenthesis space
    T o t a l space t i m e space t a k e n space = fraction numerator D divided by 2 over denominator 20 end fraction equals D over 40
    t i m e space t a k e n space i n space 2 n d space h a l f space equals left parenthesis d i s tan c e space o f space 2 n d space h a l f space j o u r n e y space right parenthesis divided by left parenthesis A v g. s p e e d space o f space 2 n d space j o u r n e y right parenthesis space
    T o t a l space t i m e space t a k e n space = fraction numerator D divided by 2 over denominator x end fraction equals fraction numerator D over denominator 2 x end fraction
    Step 2:- Equating total time taken in journey.
    Total time = time covered in 1st half + time covered in 2nd half
    D over 24 equals D over 40 plus fraction numerator D over denominator 2 x end fraction not stretchy rightwards double arrow 1 over 12 equals 1 over 20 plus 1 over x
    not stretchy rightwards double arrow 1 over 12 minus 1 over 20 equals 1 over x not stretchy rightwards double arrow fraction numerator 20 minus 12 over denominator 240 end fraction equals 1 over x
    not stretchy rightwards double arrow I over x equals 8 over 240 not stretchy rightwards double arrow x equals 240 divided by 8
    therefore space x space equals space 30
    ∴The average speed covered by bus in the second half of the journey = 30kmph.

    Related Questions to study

    card img

    With Turito Academy.

    card img

    With Turito Foundation.

    card img

    Get an Expert Advice From Turito.

    Turito Academy

    card img

    With Turito Academy.

    Test Prep

    card img

    With Turito Foundation.