Question

On a 120km track, a train travels the first 30 km at a uniform speed of 30 km/hr.
How fast must the train travel the next 90km so as to average 60km/hr for the entire trip..?
Explanation required​

Answer 1

Answer:

90kmph

Explanation:

taking speed s1=30kmph

we have to calc. s2

also we have to calc. average that means {(s1 + s2)/2} =60kmph(given)

now calc. s2 .

let me know if it was helpful

Answer 2

Explanation:

take speed =s1=30 kmph

calculate s2

we have to calculate.average that means {(s1+s2)/2} = 60 kmph(given)

now calculate s2.

Or

Take

60=(d1+d2)/(t1+t2)

This will also help you

where t1=1

And let t2=x

Then calculated it

s2=d2/t2