If 1/3 + 1/2 + 1/x = 4, then x = A. 5/18 B. 6/19 C. 24/11 D. 19/6 E. 18/5
(B) To solve this equation, we first need to find a common denominator to simplify the equation. The lowest common denominator is 3 × 2 × x = 6x. If we multiply the both sides of the equation by 6x, we can get rid of all of the fractions.
Multiplying 1/3 + 1/2 + 1/x = 4 by 6x, we get: 6x/3 + 6x/2 + 6x/x = 4(6x).
Reducing this, we get: 2x + 3x + 6 = 24x 5x + 6 = 24x 6 = 19x, or x = 6/19.
Now you might be tempted to stop there, but if you have extra time you can double check by backsolving in for x. You can plug in 6/19 for x. 1/(6/19) is the same as 19/6. 1/2 = 3/6 and 1/3 = 2/6 so you can put everything in terms of 6ths and get: 2/6 + 3/6 + 19/6 = 24/6 = 4.
So, you can see with 100% certainty that the answer of 6/19 is correct.
The correct answer is choice (B). ---------- Hi. I didn't understand why we have to multiply both sides of the equation. What I did is finding LCD that is 6, and I did not multiply 4 by 6...
Users browsing this forum: Google [Bot] and 2 guests
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot post attachments in this forum
GMAT(TM) and GMAT CAT (TM) are registered trademarks of the Graduate Management Admission Council(TM). The Graduate Management Admission Council(TM) does not endorse, nor is affiliated in any way with the owner or any content of this site.