A lake has a circumference of two kilometers. A and B both departed fr

Question

A lake has a circumference of two kilometers. A and B both departed from the same point on the circumference at the same time and walked in opposite directions. They met 30 minutes after their departure. What is the sum of the speeds of A and B?

A. 3 km/hr 
B. 4 km/hr 
C. 5 km/hr 
D. 6 km/hr 
E. 7 km/hr

vishalkazone · Answer

Answer : B

distance covered by A and B in 30 minutes is = 2 Km. ( Circumference of the lake)

combined speed= 4 km/hr

Answer B

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Kinshook · Answer

Given:  A lake has a circumference of two kilometers. A and B both departed from the same point on the circumference at the same time and walked in opposite directions. They met 30 minutes after their departure.

Asked:  What is the sum of the speeds of A and B?

Total distance = 2 km
Total time = 30 min = .5 hour

Sum of speeds of A & B = 2 /. 5 = 4 km/hr

IMO B

adstudy · Answer

Total Speed =  \frac{Total Distance}{Total Time Taken}  --- (1)

Let distance covered by A be = x km

So, distance covered by B will be = (2 - x) km

Hence total distance covered = x + (2-x) =  2 Km  --- (2)

As both A and B meet in 30 mins, so total time taken =  30 mins or 0.5 Hours  --- (3)

Using (1), (2) and (3), we get -

Total Speed =  \frac{2 Km}{0.5 Hours}

=  4 Km/hr   ---- (B)

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MathRevolution · Answer

=>

Let  a  and  b  be the velocities of  A  and  B,  respectively.

Then  (\frac{30}{60})a + (\frac{30}{60})b = (\frac{1}{2})a + (\frac{1}{2})b = 2.

Thus,  a + b = 4.

Therefore, B is the answer.
Answer: B

TheNightKing · Answer

Both A and B travel 2KMs in half an hour. So they will travel 4KM in an hour. Hence Speed of A+B is 4KM/hr

noushy · Answer

Let their speeds be X and Y,

here distance/circumference = 2km

relative speed= X+Y (as they go opposite)

we know, T=distance/speed

therefore, 1/2= 2/X+Y 
  X+Y= 2*2= 4km/hr (ans)

noushy · Answer

Let their speeds be X and Y,

here distance/circumference = 2km

relative speed= X+Y (as they go opposite)

we know, T=distance/speed

therefore, 1/2= 2/X+Y 
  X+Y= 2*2= 4km/hr (ans)

rajdeep212003 · Answer

This is so helpful it will be great to try it

A lake has a circumference of two kilometers. A and B both departed fr

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A lake has a circumference of two kilometers. A and B both departed fr

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