Question

the distance between two stations is 200 km a train travel first 100km at the speed of 10 km/h how far should the train travelrest of the distance so as to average 70 km/h for the whole journey

Answer 1

Explanation:

as per your question

total distance is 200km = d

we know that distance travelled equal to speed by time

from that we can say that

d= speed / time ;

time = 70/200=7/20 is eqn 1

d=d1+d2; s=s1+s2; t =t1+t2.

t1=s1/d1

t1= 10/100=1/10

t2= s1/100

we know that

t=t1+t2 which is

7/20 - 1/10= s1/100

5/20 *100= s1

s1=5*5 = 25.

is ur required answer

hope you understand my explanation

all the best..