Name:
Anonymous
2005-12-07 19:33
When you multiply 2^1990 by 5^1991 you get a product with 1991 digits. What is the sum of all of these digits?
Name:
Anonymous
2005-12-08 0:20
5^1 } 5
5^2 = 25 } 7
5^3 = 125 } 8
5^4 = 625 } 13
5^5 = 3125 } 11
5^6 = 15625 } 19
5^7 = 78125 } 26
5^8 = 390625 } 25
1: Find pattern.
2: ???
3: Profit.