Bhavna arranges small identical dots in successive horizontal rows so that the first…
MATHEMATICS · Subjective · CBSE · Mathematics · Number Play · Number Play
Problem
Bhavna arranges small identical dots in successive horizontal rows so that the first row has 1 dot, the second row has 2 dots, the third row has 3 dots and so on until the nth row.
(i) For n = 5, list the number of dots in each row and determine the total number of dots in the arrangement.
(ii) Based on your observation in part (i), write an expression in terms of n for the total number of dots when there are n rows.
(iii) Justify the expression obtained in part (ii) by pairing rows in a suitable manner.