Problem:
What is the value in simplest form of the following expression?
1+1+3+1+3+5+1+3+5+7
Answer Choices:
A. 5
B. 4+7+10
C. 10
D. 15
E. 4+33+25+7
Solution:
We have
1+1+3+1+3+5+1+3+5+7=1+4+9+16=1+2+3+4=(C)10
Note: This comes from the fact that the sum of the first n odds is n2.
The problems on this page are the property of the MAA's American Mathematics Competitions