SOLUTION: Rob is playing with building blocks. The top row has one block, the second row has three the third has five and so on. How many rows can she make with a set of 100 blocks.

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Question 775624: Rob is playing with building blocks. The top row has one block, the second row has three the third has five and so on. How many rows can she make with a set of 100 blocks.
Answer by psbhowmick(878) About Me  (Show Source):
You can put this solution on YOUR website!
This is a problem of Arithmetic Progression. The first term is 1 and the common difference is 2 and sum of first N terms is 100. We are supposed to find the value of N.
Using the summation formula:
%282a%2B%28N-1%29d%29%2AN%2F2+=+S%5BN%5D
%282%2A1%2B%28N-1%29%2A2%29%2AN%2F2+=+100
%282%2B2N-2%29%2AN%2F2+=+100
N%5E2+=+100
N=10

Therefore, 10 rows of blocks can be created.