On monday Rhonda made an average of 12 phone calls per hour for the fi

Question

On monday Rhonda made an average of 12 phone calls per hour for the first 6 calls she made , and then an average of 6 phone calls per hour for the remaining 6 calls she made. What was the average number of phone calls per hour that Rhonda made for the entire day

(a) 7.5
(b) 8.0
(c) 9.5
(d) 10.0
(e) 10.5

(a) 7.5
(b) 8.0
(c) 9.5
(d) 10.0
(e) 10.5

nmccull · Answer

12 phone calls per hour for first 6 calls = 30 minutes total for the first 6 calls
6 phone calls per hour for last 6 calls = 1 hour total for the last 6 calls

12 total phone calls over 1.5 hour = 12/1.5 = 8

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chetan2u · Answer

So, there are two sets of 6 calls made at two different frequencies.
let us calculate the time for these..

(i) 6 calls at the rate of 12 calls per hour..
If 12 calls in one hour, 6 calls will be made in  6*\frac{1}{12}=\frac{1}{2} hr

(ii) 6 calls at the rate of 6 calls per hour..
so 1 hour for these calls.

Thus, total calls = 6+6 or 12 calls, and time taken =  1+\frac{1}{2}=\frac{3}{2} hr
Average calls per hour =  \frac{calls}{time}=12/\frac{3}{2}=\frac{12*2}{3}=8 calls per hour.

B

CAMANISHPARMAR · Answer

This question can be solved by dividing the total number of calls by total time, i.e. 12/1.5 = 8 calls per hour

ScottTargetTestPrep · Answer

Since she made the first 6 calls in 6/12 = 1/2 hour and the next 6 calls in 6/6 = 1 hour, her average number of phone calls per hour is:

(6 + 6)/(1/2 + 1) = 12/(3/2) = 12 x 2/3 = 8

Answer: B

chetan2u · Answer

Hi
You should be careful with Allegations method as it cannot be used everywhere .
Here the 12per hour will work out only for half an hour as only 6 calls are made . This case requires following formula for same work in different time..
2ab/(a+b) = 2*12*6/(12+6) = 8

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On monday Rhonda made an average of 12 phone calls per hour for the fi

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