If a racehorse runs an average(arithmetic mean) of m miles per race fo

Question

If a racehorse runs an average(arithmetic mean) of m miles per race for r races and then runs n miles in its next race, what is the average number of miles the horse has run for the r + 1 races?

a) (rm + n)/r+1
b) (m + n)/r+1
c) (m + n)/r
d) r(m + n)/r+1
e) (m + rn)/r+1

Please assist with above problem.

gauravk · Answer

Average miles ran per race = m for r no of races. So total miles = m*r

Miles ran in next race = n

Total Miles ran = m*r + n in r+1 races

Average miles = Total miles/Total no of races = (m*r + n)/(r + 1)

Option A

HTH

Abhishek009 · Answer

Total distance run in  r  races =  rm 
Distance run in last race is  n

So, Total Distance Run =  rm   +   n 
Total run =  r + 1

Hence average will be  \frac{rm + n}{r+1} 
  
So, Correct answer will be (A)

ScottTargetTestPrep · Answer

We are given that a racehorse runs an average (arithmetic mean) of m miles per race for r races and then runs n miles in its next race. We need to determine the average number of miles the horse has run for r + 1 races. Let’s plug the given information into the average formula.

average = sum/quantity

Since the racehorse runs an average (arithmetic mean) of m miles per race for r races, the initial sum = mr and the initial quantity is r.

Since the racehorse then runs n miles in its next race, the new sum is mr + n and the new quantity is r + 1.

Thus, the average number of miles that the horse runs for r + 1 races is:

(mr + n)/(r + 1)

Answer: A

EMPOWERgmatRichC · Answer

Hi All,

This question can be solved Algebraically or by TESTing VALUES. Here's how you can use the second method:

IF... 
M = 2 
R = 3 
Then the racecourse ran (2 miles/race)(3 races) = 6 miles

N = 4 
So the horse ran 4 miles in that 1 race.

Thus, the average for the 4 races was (10 miles)/(4 races) = 2.5 miles/race

There's only one answer that matches...

Final Answer:  A

GMAT assassins aren't born, they're made, 
Rich

Abhishek009 · Answer

Total distance run in r races is  mr  
Total distance run after n miles is  mr + n

So, Average Distance run is  \frac{mr + n}{r + 1}  , Answer must be (A)

bumpbot · Answer

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If a racehorse runs an average(arithmetic mean) of m miles per race fo

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If a racehorse runs an average(arithmetic mean) of m miles per race fo

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