math
posted by Cortez on .
manfred mouse fell inside a box of toy blocks. to escape, he needs to build a stairway with the blocks. for manfred to escape, the stairway must be 8 blocks high. he starts with 8 blocks for the bottom step. for the next step, he lays 7 blocks atop the first set of blocks. if he continues this pattern how many blocks will he need in all to build the staiway?

Wont the average be(81)*8/2=28 blocks.
Count them to check. 
6+5+4+3+2+1=21 blocks