In a small snack shop, the average (arithmetic mean) revenue was $400 per day over a 10-day period. During this period, if the average daily revenue was $360 for the first 6 days,what was the average daily revenue for the last 4 days?
A. $420
B. $440
C. $450
D. $460
E. $480
5-Day Free Trial
5-day free, full-access trial TTP
Available with Beat the GMAT members only code
MORE DETAILS
In a small snack shop.......
This topic has expert replies
Answer is D
Total revenue over the 10 day period: 400 * 10 = 4000
Total rev for first 6 days: 360*6 = 2160
Total revenue for the next 4 days = 4000 -2160 = 1840
Therefore, Avg revenue for the next 4 days = 1840/4 = 460
Total revenue over the 10 day period: 400 * 10 = 4000
Total rev for first 6 days: 360*6 = 2160
Total revenue for the next 4 days = 4000 -2160 = 1840
Therefore, Avg revenue for the next 4 days = 1840/4 = 460
Thanks!
- Treker
- Treker
-
Testluv
- GMAT Instructor
- Posts: 1302
- Joined: Mon Oct 19, 2009 2:13 pm
- Location: Toronto
- Thanked: 539 times
- Followed by:164 members
- GMAT Score:800
We can also solve this through the balanced scale concept.
The overall average is $400.
The first 6 days' average is $360. So, on each of these 6 days, we are short $40 from the average (400-360). Thus, we have to make up 6*$40 = $240.
So, we have to "spread" an extra $240 across the last 4 days. That's an extra 240/4 = $60 beyond $400. And, 60 + 400 = 460.
The overall average is $400.
The first 6 days' average is $360. So, on each of these 6 days, we are short $40 from the average (400-360). Thus, we have to make up 6*$40 = $240.
So, we have to "spread" an extra $240 across the last 4 days. That's an extra 240/4 = $60 beyond $400. And, 60 + 400 = 460.
Kaplan Teacher in Toronto
treker wrote:Answer is D
Total revenue over the 10 day period: 400 * 10 = 4000
Total rev for first 6 days: 360*6 = 2160
Total revenue for the next 4 days = 4000 -2160 = 1840
Therefore, Avg revenue for the next 4 days = 1840/4 = 460
thank you....i understood how to solve it............
