Question Details

If m and n are natural numbers such that n > 1, and mn = 225 ×340, then m−n equals to.

Options

A

209942

B

209947

C

209932

D

209937

Show Answer

Correct Answer :

Option A

209942

Solution :

The correct option is 209942.

We are given that m and n are natural numbers such that n>1, and we are given the equation:

mn=225×340

To find the values of m and n, we need to express the right-hand side in the form of BaseExponent, where the exponent n is a natural number greater than 1.
Let's find the greatest common divisor (GCD) of the exponents 25 and 40.
The factors of 25 are 1 and 5.
The factors of 40 are 1, 2, 4, 5, 8, 10, 20, and 40.
Thus, the greatest common divisor of 25 and 40 is:

GCD(25,40)=5

Since n>1 must be a common divisor of the exponents 25 and 40 for m to be an integer (specifically, a natural number), n must divide both 25 and 40. The common divisors of 25 and 40 are 1 and 5.
Since we are given that n>1, the only possible value for n is:

n=5

Now, we rewrite the equation by expressing the exponents in terms of 5:

m5=25×5×38×5

Using the laws of exponents, ax·y=(ax)y, we can rewrite the terms as follows:

m5=(25)5×(38)5

Combining the terms under a single exponent, we get:

m5=(25×38)5

Taking the 5th root on both sides, we find the value of m:

m=25×38

Let's calculate the values of 25 and 38:
25=32
38=(34)2=812=6561

Now, calculate m by multiplying these two values:

m=32×6561

Let's perform the multiplication:
32×6561=32×(6500+61)=208000+1952=209952

So, we have:

m=209952

We are asked to find the value of mn:
Substitute the values of m and n:

mn=2099525=209942

Thus, mn equals 209942.

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