2007 AMC 8 Problems/Problem 7
Contents
Problem
The average age of people in a room is
years. An
-year-old person leaves
the room. What is the average age of the four remaining people?
Solution 1
Let be the average of the remaining
people.
The equation we get is
Simplify,
Therefore, the answer is
Solution 2
Since an year old left from a group of people averaging
, The remaining people must total
years older than
. Therefore, the average is
years over
. Giving us
Solution 3
The total ages would be . Then, if one
year old leaves, we subtract
from
and get
. Then, we divide
by
to get the new average,
Video Solution by SpreadTheMathLove
https://www.youtube.com/watch?v=omFpSGMWhFc
See Also
2007 AMC 8 (Problems • Answer Key • Resources) | ||
Preceded by Problem 6 |
Followed by Problem 8 | |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25 | ||
All AJHSME/AMC 8 Problems and Solutions |
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions.