Latest Elitmus Aptitude Question SOLUTION: 1/m+4/n=1/12 Where n is an odd integer less than 60 ?? A. 4 B. 7 C. 5 D. 3

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(#M40062058) ELITMUS Numerical Ability question number system - elitmus Keep an EYE

1/m+4/n=1/12
Where n is an odd integer less than 60 ??

A. 4
B. 7
C. 5
D. 3

Asked In Elitmus kashish (9 years ago)

Solved prasoon Read Solution (3)

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Read Solution (3) :

ANUSHA Y  (9 years ago)

1/m + 4/n = 1/12
Since we know something about n, so express m as the value of n.
=> 1/m = 1/12 - 4/n
=> 1/m = (n-48)/(12*n)
=> m = (12*n)/(n-48)

Now since n is odd +ve integers less than 60.
So, n must be greater than 48 so than value of m is +ve.
So range of n is: [49, 59] and only odd numbers.
Hence, n can be: (49,51,53,55,57,59)

From here we can see clearly that for n = 49, 51 and 57, we get positive integer value for m.
So there are 3 possible values for pair (m,n)

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prasoon  (9 years ago) Best Solution

Since m and n are positive, n should be greater than 48 ( so that m is positive). So n can be 49, 51, 53, 55, 57, 59.

Let us take each values :

n = 49, m = 12 * 49/1 Both m & n are positive and integers.
n = 51, m = 12 * 51/3 Both m & n are positive and integers.
n = 53, m = 12 * 53/5 Both m & n are positive but m is not an integer.
n = 55, m = 12 * 55/7 Both m & n are positive but m is not an integer.
n = 57, m = 12 * 57/9 Both m & n are positive and integers.
n = 59, m = 12 * 59/11 Both m & n are positive but m is not an integer.

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Mithun Kumar Kesari  (9 years ago)

answer D

n is inter and =48.

now for n=48, m=0

for n=52, m=12*13

for n=56, m= 12*7

so only three whole value of m are possible.

Is this solution Helpfull? Yes (4) | No (1)  

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