8. In the above correctly worked addition sum, A,B,C and D

This topic has expert replies
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 511
Joined: Wed Aug 11, 2010 9:47 am
Location: Delhi, India
Thanked: 344 times
Followed by:86 members

by Anju@Gurome » Wed Apr 24, 2013 4:07 am
varun289 wrote:5A
BC
-----
D43

In the above correctly worked addition sum, A,B,C and D represent different digits, and all the digits in the sum are different. What is the sum of A,B,C and D?
5A and BC are two 2-digit integers, where A, B, and C are different digits, and none of them are equal to 3 or 4 or 5.
So, the maximum value of the sum of 5A and BC is (98 + 57) = 155
So, possible values of D are 0 and 1.
But the sum cannot be 43 as it must be greater than 5A.
So, D = 1

Now, units digit of (A + C) is 3.
So, possible values of (A, C) are : (0, 3), (1, 2), (4, 9), (5, 8), and (6, 7)
As none of A and C can be equal to 1 or 3 or 4 or 5, only possible pair is (6, 7)

Now, (A + C) will result in a carry of 1.
So, (5 + B + 1) = 14 ---> B = 8

Hence, (A + B + C + D) = (6 + 8 + 7 + 1) = 22

The correct answer is B.
Anju Agarwal
Quant Expert, Gurome

Backup Methods : General guide on plugging, estimation etc.
Wavy Curve Method : Solving complex inequalities in a matter of seconds.

§ GMAT with Gurome § Admissions with Gurome § Career Advising with Gurome §

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 Apr 24, 2013 5:05 am
varun289 wrote:5A
BC
-----
D43

8. In the above correctly worked addition sum, A,B,C and D represent different digits, and all the digits in the sum are different. What is the sum of A,B,C and D?

A. 23
B. 22
C. 18
D. 16
E. 14
On the GMAT, D43 would represent a 3-digit integer, implying that D>0.
Since 99+99 = 198, D43 < 198.
Thus, D43 = 143, and D=1.
Since no digit can be repeated, 5A = 50, 52, 56, 57, 58, or 59.

Case 1: 5A = 50
Here, BC = 143-50 = 93.
Not viable, since 3 cannot appear in both 143 and 93.

Case 2: 5A = 52
Here, BC = 143-52 = 91.
Not viable, since 1 cannot appear in both 143 and 91.

Case 3: 5A = 56
Here, BC = 143-56 = 87.
This works: A=6, B=8, C=7, and D=1, with no digit appearing more than once.

Thus, A+B+C+D = 6+8+7+1 = 22.

The correct answer is B.
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