What is the average (arithmetic mean) of x and y?

This topic has expert replies
Moderator
Posts: 2058
Joined: Sun Oct 29, 2017 4:24 am
Thanked: 1 times
Followed by:5 members
What is the average (arithmetic mean) of x and y?

(1) The average of x + 3 and y + 5 is 14.
(2) The average of x, y, and 16 is 12.

The OA is the option D .

I know that the statement (2) is sufficient. But, how can I prove that the statement (1) is sufficient?

Senior | Next Rank: 100 Posts
Posts: 94
Joined: Tue Dec 16, 2014 9:50 am
Location: London, UK
Thanked: 2 times
Followed by:4 members
GMAT Score:770

by mbawisdom » Tue Mar 06, 2018 4:21 am
M7MBA wrote:What is the average (arithmetic mean) of x and y?

(1) The average of x + 3 and y + 5 is 14.
(2) The average of x, y, and 16 is 12.

The OA is the option D .

I know that the statement (2) is sufficient. But, how can I prove that the statement (1) is sufficient?
Avg = (x + y)/2 --> we need to be able to find x + y

(1) SUFFICIENT

(x + 3 + y + 5)/2 = 14
x + y + 8 = 28
x + y = 20
(x + y)/2 = 10

(2) SUFFICIENT

(x + y + 16)/3 = 12
x + y + 16 = 36
x + y = 20
(x + y)/2 = 10

User avatar
Legendary Member
Posts: 1100
Joined: Sat May 10, 2014 11:34 pm
Location: New Delhi, India
Thanked: 205 times
Followed by:24 members

by GMATinsight » Fri Mar 09, 2018 6:34 am
M7MBA wrote:What is the average (arithmetic mean) of x and y?

(1) The average of x + 3 and y + 5 is 14.
(2) The average of x, y, and 16 is 12.

The OA is the option D .

I know that the statement (2) is sufficient. But, how can I prove that the statement (1) is sufficient?
Question : Average of a and b = ?

i.e. Question : x+y = ?

Statement 1: The average of x + 3 and y + 5 is 14.

(x+3)+(y+5) = 2*14
i.e. x + y = 20
SUFFICIENT

Statement 2: The average of x, y, and 16 is 12

i.e. x+y+16 = 12*3
i.e. x + y = 20
SUFFICIENT

Answer: option D
"GMATinsight"Bhoopendra Singh & Sushma Jha
Most Comprehensive and Affordable Video Course 2000+ CONCEPT Videos and Video Solutions
Whatsapp/Mobile: +91-9999687183 l [email protected]
Contact for One-on-One FREE ONLINE DEMO Class Call/e-mail
Most Efficient and affordable One-On-One Private tutoring fee - US$40-50 per hour