jmc

Question

The fifth term of an arithmetic sequence is 11. If the difference between two consecutive terms is 1, what is the product of the first two terms?

Accepted Answer

Simply back up from 11. Since 11 is the fifth term, the first term will be 11 - 4 1 = 7, and the second term will be 11 - 3 1 = 8. So the answer is 7 8 = 56.