Difference between revisions of "2007 AMC 8 Problems"
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For any positive integer <math>n</math>, <math>\boxed{n}</math> to be the sum of the positive factors of <math>n</math>. | For any positive integer <math>n</math>, <math>\boxed{n}</math> to be the sum of the positive factors of <math>n</math>. | ||
− | For example, 6 = 1 + 2 + 3 + 6 = 12. Find <math>\boxed{ | + | For example, 6 = 1 + 2 + 3 + 6 = 12. Find <math>\boxed{\boxed{11}}</math> . |
(A) 13 (B) 20 (C) 24 (D) 28 (E) 30 | (A) 13 (B) 20 (C) 24 (D) 28 (E) 30 |
Revision as of 14:43, 15 February 2010
Contents
- 1 Problem 1
- 2 Problem 2
- 3 Problem 3
- 4 Problem 4
- 5 Problem 5
- 6 Problem 6
- 7 Problem 7
- 8 Problem 8
- 9 Problem 9
- 10 Problem 10
- 11 Problem 11
- 12 Problem 12
- 13 Problem 13
- 14 Problem 14
- 15 Problem 15
- 16 Problem 16
- 17 Problem 17
- 18 Problem 18
- 19 Problem 19
- 20 Problem 20
- 21 Problem 21
- 22 Problem 22
- 23 Problem 23
- 24 Problem 24
- 25 Problem 25
- 26 See also
Problem 1
Theresa's parents have agreed to buy her tickets to see her favorite band if she spends an average of hours per week helping around the house for
weeks. For the first
weeks she helps around the house for
,
,
,
and
hours. How many hours must she work for the final week to earn the tickets?
Problem 2
students were surveyed about their pasta preferences. The choices were lasagna, manicotti, ravioli and spaghetti. The results of the survey are displayed in the bar graph. What is the ratio of the number of students who preferred spaghetti to the number of students who preferred manicotti?
![AMC8 2007 2.png](https://wiki-images.artofproblemsolving.com//a/a3/AMC8_2007_2.png)
Problem 3
What is the sum of the two smallest prime factors of ?
Problem 4
A haunted house has six windows. In how many ways can Georgie the Ghost enter the house by one window and leave by a different window?
Problem 5
Chandler wants to buy a mountain bike. For his birthday, his grandparents
send him
, his aunt sends him
and his cousin gives him
. He earns
per week for his paper route. He will use all of his birthday money and all
of the money he earns from his paper route. In how many weeks will he be able
to buy the mountain bike?
Problem 6
The average cost of a long-distance call in the USA in was
cents per minute, and the average cost of a long-distance
call in the USA in
was
cents per minute. Find the
approximate percent decrease in the cost per minute of a long-
distance call.
Problem 7
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?
Problem 8
In trapezoid ,
is perpendicular to
,
=
=
, and
=
. In addition,
is on
, and
is parallel to
. Find the area of
.
![AMC8 2007 8.png](https://wiki-images.artofproblemsolving.com//f/f2/AMC8_2007_8.png)
Problem 9
To complete the grid below, each of the digits 1 through 4 must occur once in each row and once in each column. What number will occupy the lower right-hand square?
![AMC8 2007 9.png](https://wiki-images.artofproblemsolving.com//e/e5/AMC8_2007_9.png)
cannot be determined
Problem 10
For any positive integer ,
to be the sum of the positive factors of
.
For example, 6 = 1 + 2 + 3 + 6 = 12. Find
.
(A) 13 (B) 20 (C) 24 (D) 28 (E) 30