Question

Rama has arranged 256 dots to draw a rangoli in the following ways. In how many

rows has she arrange the dots 1 in first row 3 in second 5 in third and soon

Answer 1

Rama has arranged dots in ascending order i.e. 1, 3, 5.....

AP = 1, 3, 5.....
where, a = 1, d = 2 and Sn = 256

we have to find out no of rows.
Apply the formula,

=> Sn = n/2 ( 2a + (n-1) d )

=> 256 = n/2 [ 2*1 + (n-1) 2 ]

=> 256 = n/2 ( 2+ 2n - 2)

=> 256 = n/2 * 2n

=> 256 = n²

=> n= 16

Required answer is 16.