Expert: Richard J. Raridon - 5/26/2004

Question
1) to begin the hlaf-time performance, a high school band marches onto the football field in a pyramid formation. the drum major leads the band alone in the first row. there are 2 band members in the 2nd row, 3 in the 3rd row, 4 in the 4th row, and so on. the pyramid formation has 15 rows. how many members does the band have?

Answer
Basically, you want the sum of the numbers from 1 through 15.   Look at it this way
1+15 = 16
2+14 = 16
....
....
7+9 = 16
so you have 7 pairs of numbers, each of which adds up to 16
and the sum is 7(16) = 112 and then you have to add 8 for the eighth row for a total of 120