Question

A gable end is built with 24 bricks in the lowest row, and one less brick in each row than in the row beneath. Find the total number of bricks required.

Answer 1

Step-by-step explanation:

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Answer 2

300 bricks.

Step-by-step explanation:

A gable end is built with 24 bricks in the lowest row, and one less brick in each row than in the row beneath.

So, there will be a total 24 rows of bricks.

Now, in the 1st row (taken from low to high), there are 24 bricks and in the 2nd row, there are 23 bricks and in the 3rd row, there are 22 bricks and so on.

Therefore, total number of bricks required will be

= (24 + 23 + 22 + ....... + 1)

= 1 + 2 + 3 + .......... + 23 + 24

= $\frac{1}{2} \times 24 \times (24 + 1) = 300$ (Answer)

Note: Sum of n natural numbers i.e. 1 + 2 + 3 + ...... + n = $\frac{1}{2}\times n\times (n + 1)$.