Question

Ronnie is building a triangular wall with bricks. The top row has one brick, the second row has three bricks, the third row has five, and so on. How many bricks will it take to build 10 rows

Answer 1

100

Explanation:

1+3+5+7+9+11+13+15+17+19

=1+19 +3+17 ... + 9+11

= 20+20+...20

=5*20 =100