Aptitude - Time and Distance - Discussion

Thanks @Sundar.

First 160 km: Speed is 64 kmph.
Second 160 km:- Speed is 80 kmph.

So, just use Average speed = (2xy)/x+y = (2*64*80)/64+80 = 71.11 kmph.

For 1st 160km time taken will be =160/64 = 2.5 sec.
For 2nd 160km time taken will be = 160/80 = 2 sec.

Total time taken in journey = 2.5 + 2 = 4.5 sec.

The avg speed for 320 km will be=total distance travelled/total time.
So,, 320/4.5 = 71.11 kmph.

We can apply 2xy/x+y.

Am I right?

Formula use to average speed is 2xy/x+y.
First speed is x = 64,
Second speed is y = 80.
Put the speeds values in the formula.
= 2xy/x+y.
= 2x64x80/64+80,
= 10240/144,
= 71.1111 km/hr ans.

Can we use Average = (80+64)/2?

Anyone, Please tell me.

We can use,
Avg= 64 + 80/2.
= 144/2.
= 72 kmph.
= 72

So, here the answer is 71.11 kmph.

Total distançe = 160+160=320
Total time = 160/64+160/80 = 4.5 = 9/2.
Av speed = TD/TT.
= 320/9/2.
= 71.11km/h.

To find the average speed for the first 320 km of the tour, we can use the formula for average speed, which is the total distance traveled divided by the total time taken.

Given:

Distance 1 = 160 km
Speed 1 = 64 km/hr
Distance 2 = 160 km
Speed 2 = 80 km/hr.

We can calculate the total time taken for the first 320 km as follows: Time taken for the first 160 km = Distance 1/Speed 1 Time taken for the next 160 km = Distance 2/Speed 2.

Total time taken = Time taken for the first 160 km + Time taken for the next 160 km.

Total time taken = (Distance 1/Speed 1) + (Distance 2/ Speed 2)
Total time taken = (160/64) + (160/80).

Now, we can find the average speed: Average speed = Total distance / Total time taken Average speed = (Distance 1 + Distance 2)/Total time taken Average speed = 320/ ((160/64) + (160/80)).

By evaluating the expression, we can find the average speed for the first 320 km of the tour.

Avg speed = TD/TT.
Total Distance (TD) = 160 + 160 = 320 km.
Total Time (TT) =160/64 + 160/80 = 9/2 hr.
Avg speed = 320 * 2/9 = 71.11km/hr.