a DS question but what if we were to solve

Expert replies

shoot4greatness: Master | Next Rank: 500 Posts; Posts: 100; Joined: Sat Sep 11, 2010 6:57 pm; Thanked: 2 times

by shoot4greatness » Tue May 31, 2011 12:34 pm

the inflation index for the year 1989 relative to the year 1970 was 3.56, indicating that, on the average, for each dollar spend in 1970 for goods, $3.56 had to be spent for the same goods in 1989. If the price of Model K mixer increased precisely according to the inflation index, what was the price of the mixer in 1970?

1. the price of the Model K mixer was $102.40 more in 1989 than in 1970

2. the price of the model K mixer was $142.40 in 1989

The answer is d

if we were to solve, for instance 1, do we divide the 102.40 by the inflation index to solve for the price in 70 or do we just leave the increase as is?

Last edited by shoot4greatness on Tue May 31, 2011 2:59 pm, edited 1 time in total.

Like this post

Source: Beat The GMAT — Problem Solving | Tue May 31, 2011 12:34 pm

bajwa2307: Senior | Next Rank: 100 Posts; Posts: 40; Joined: Tue Jan 18, 2011 5:14 amFollowed by: 2 members; Location: Bangalore; Thanked: 3 times

by bajwa2307 » Tue May 31, 2011 12:53 pm

are you sure that the answer is c?

let price in 1970 be x
let price in 1989 be y

so by statement 1, we have

y - x = 102.40

now we know that 3.56x = y

so substitute the value of y in equation and solve for X, hence 1 is sufficient

by using statement 2, we have

y = 142.40

use the relation, 3.56x = y

substitute the value of y and solve for x, so 2 alone is also sufficient

I think the answer should be D or am I doing something wrong here?

Verbal is testing my patience

Like this post

SoCan: Senior | Next Rank: 100 Posts; Posts: 97; Joined: Sun May 15, 2011 9:19 amFollowed by: 1 member; Thanked: 18 times

by SoCan » Tue May 31, 2011 1:33 pm

Answer is definitely D, not C

x=price in 1970

1) x=(x+102.4)/3.56
3.56x=x+102.4
2.56x=102.4
x=40

2) x=142.40/3.56
x=40

What source gave you C?

Like this post

shoot4greatness: Master | Next Rank: 500 Posts; Posts: 100; Joined: Sat Sep 11, 2010 6:57 pm; Thanked: 2 times

by shoot4greatness » Tue May 31, 2011 2:57 pm

Sorry typo yes its d

Like this post

serendipiteez: Junior | Next Rank: 30 Posts; Posts: 25; Joined: Wed Feb 13, 2013 9:25 pm; Thanked: 2 times

by serendipiteez » Sun May 26, 2013 4:40 am

My gut feel was "How does knowing what it increased by tell me anything about the original price?" and then I moved on. But clearly, there's an algebraic solution.

Generally speaking, if we know the difference in prices between two dates like this example, can we always solve and get an answer?

I'm trying to understand whether this is just a special case where it just worked out or can this be taken as a general rule?

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

560 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review