Question 781726

A Cyclist covers a certain distance in 3 1/2 hours.If first half of the journey is covered in 20 km/hr and the rest of the journey in 15 km/hr,find the total distance of the whole journey.


PLease help me!!


Let total distance covered be D
Then time taken to cover ˝ of total distance at 20 km/h = {{{(1/2)D/20}}}, or {{{(D/2)/20}}}, or {{{D/40}}}


Time taken to cover 2nd ˝ of total distance at 15 km/h = {{{(1/2)D/15}}}, or {{{(D/2)/15}}}, or {{{D/30}}}


Therefore, a TIME equation can be created to solve for the total distance, D. This is:
{{{D/40 + D/30 = 3.5}}}
3D + 4D = 420________Multiplying by LCD, 120
7D = 420


D, or distance traveled = {{{420/7}}}, or {{{highlight_green(60)}}} km


You can do the check!! 


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