Problem:
What is the value of:
31⋅42⋅53⋯2018⋅2119⋅2220?
Answer Choices:
A. 4621
B. 2311
C. 1321
D. 2132
E. 221
Solution:
Note that all the numbers cancel except for the first two in the numerator and the last two in the denominator. The value of the product is
31⋅42⋅53...2018⋅2119⋅2220=31⋅42⋅53...2018⋅2119⋅2220
=11⋅12⋅211⋅211=2311.
Answer: B.
The problems on this page are the property of the MAA's American Mathematics Competitions