If 5^5 × 5^7 = (125)^x , then what is the value of x?

Question

Tough and Tricky questions: Exponents.

A) 2
B) 3
C) 4
D) 5
E) 6

Kudos for a correct  solution .

Source: Chili Hot GMAT

omegacube · Answer

5^5 × 5^7 = 5^(5 + 7) = 5^12
125^3 = (5^3)^3 = 5^3X

Therefore 3x = 12, x = 4

Hence C

amitshri15 · Answer

5^5 = 125 x25 and 5^7 = 5* 125^2

5^5 * 5^7 = 125^4 hence x= 4.

Answer is C.

intheend14 · Answer

Get everything in base 5 first: 5^5*5^7=125^x=5^(3x)
When multiple two identical bases with exponents, simply add the exponents together: 5^5*5^7 = 5^12
Now we have 5^12 = 5^(3x) and we can equate the exponents when the bases are the same to get x=4.

Choice C

PareshGmat · Answer

Answer = C = 4

5^5 * 5^7 = (125)^x

5^{12} = {(5^3)}^{x}

5^{12} = 5^{3x}

Bases are same, equating powers

3x = 12

x = 4

JJo · Answer

5^5 × 5^7 = (125)^x
5^(5+7) = 5^3x
5^12 = 5^3x

since base is same, we can equate powers:
12 = 3x
x = 4

Ans. C) 4

Bunuel · Answer

The correct answer is C.

preetamsaha · Answer

If 5^5 × 5^7 = (125)^x , then what is the value of x?

5^5 × 5^7 = (125)^x
or,5^(5+7) = (5^3)^x
or,5^(12) = 5^(3x)
so,3x=12
or,x=4
 
correct answer C

If 5^5 × 5^7 = (125)^x , then what is the value of x?

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GMAT Problem Solving (PS) Questions

If 5^5 × 5^7 = (125)^x , then what is the value of x?

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