BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

RATIO AND PROPORTION

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 20
Joined: Tue Dec 18, 2012 9:24 am

RATIO AND PROPORTION

by sayanpaul » Wed Jul 03, 2013 3:39 am
Suppose y varies as the sum of two quantities of which one varies directly as x and the other inversely as x. If y = 6 when x = 4 and y = 10/3 when x = 3, then the relation between x and y is:

A. x = y+4
B. y = 2x+(8/x)
c. y = 2x-(8/x)
D. y = 2x-(4/x)
Top
Source: — Problem Solving |
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Wed Jul 03, 2013 5:43 am
sayanpaul wrote:Suppose y varies as the sum of two quantities of which one varies directly as x and the other inversely as x. If y = 6 when x = 4 and y = 10/3 when x = 3, then the relation between x and y is:

A. x = y+4
B. y = 2x+(8/x)
c. y = 2x-(8/x)
D. y = 2x-(4/x)
When x=4 is plugged into the correct answer choice, y=6.
Only C works:
y = 2x - (8/x) = 2*4 - (8/4) = 6.

The correct answer is C.
Last edited by GMATGuruNY on Thu Jul 04, 2013 7:36 am, edited 1 time in total.
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
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 283
Joined: Sun Jun 23, 2013 11:56 pm
Location: Bangalore, India
Thanked: 97 times
Followed by:26 members
GMAT Score:750

by ganeshrkamath » Thu Jul 04, 2013 2:58 am
sayanpaul wrote:Suppose y varies as the sum of two quantities of which one varies directly as x and the other inversely as x. If y = 6 when x = 4 and y = 10/3 when x = 3, then the relation between x and y is:

A. x = y+4
B. y = 2x+(8/x)
c. y = 2x-(8/x)
D. y = 2x-(4/x)
y = ax + b/x
6 = 4a + b/4 ___ (1)
10/3 = 3a + b/3 ___ (2)
from (1) 24 = 16a + b
from (2) 10 = 9a + b
14 = 7a
a = 2
b = -8

y = 2x - 8/x

So C.
Top
Post new topic Post Reply
• Page 1 of 1