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Maths Puzzle
Two cars start at the same time from A and B which are 120 km apart. If the two cars travel in opposite direction they meet after one hour and if they travel in same direction ( from A towards B) then A meets B after 6 hours. What is the speed of the car starting from A?
a) 70 kmph
b) 120 kmph
c) 60 kmph
d) Data Inadequate
e) None of these
Read Solution (Total 2)
-
- a)70kmph
Let, speed of car from A towards B = x km/ph
Let, speed of car from B towards A = y km/ph
Two cars start at same time which 120km apart = x + y = 120-----(i)
Travel in same direction, A meets B after 6hr = 6x-6y = 120-----(ii)
By Solving equation (i) and (ii), we get
12x = 840
x = 840/12
x = 70km/ph
Substituting x value in eqn (i) or (ii), we get
y = 50km/ph.
So, speed of car starting from A is 70kmph. - 13 years agoHelpfull: Yes(4) No(1)
- If they are travelling in same direction, they meet after 6 hrs.
so relative speed = diff in speeds , A-B = 120/6 = 20 kmph
They meet when travel in opposite direction in 1 hr,
in that case relative speed= sum of speeds = A+B= 120/1=120
so 2A =140
A=70 kmph - 13 years agoHelpfull: Yes(3) No(1)
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