Question

A car moves 20 kilometre with a speed of 30 kilometre per hour and next 20 km with a speed of of 60 kilometre per hour. What is the total time taken in this whole journey ?
A) 2¾ h
B) 3¼ h
C) 1 h
D) 3⅓ h​

Answer 1

Explanation:

total distance covered= 20+20= 40

total time taken = d1/ s1 + d2/ s2

= 20/30 + 20/60

now lcm then solve 40+20/60

so 60/60= 1 hr ans