gmatpup wrote:GMATGuruNY wrote:gmatpup wrote:If (1/5)^m * (1/4)^18 = 1/2(10)^35 then m = ?
A. 17
B. 18
C. 34
D. 35
E. 36
Answer is D
I am soo lost, please help!
Thanks soso much:)
No need to simplify the whole equation.
Every factor on the right side must also appear on the left side.
On the right side we have 1/10³� = 1/2³� * 1/5³�.
Thus, the left side must also include 1/5³�, implying that m=35.
The correct answer is
D.
OH! So the answer is 35 simply because this number appears on the right, thus is must also appear on the left?
I know other times when trying to find a variable you have to get like bases... how do I know when I need like bases or when it is a situation such as this?
Thanks again!!
Each side of the equation is a series of factors.
Thus, if one side has a prime number raised to a power, the other side must have the same prime number raised to the same power.
In the problem above, m appears only once -- as part of 1/(5^m) -- so this is the only factor that concerns us.
Once we recognize that the right hand side includes 1/(5³�), we know that the left hand side must also include 1/(5³�).
Thus, m=35. No need to do any more math.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at
[email protected].
Student Review #1
Student Review #2
Student Review #3
