How many numbers in the sequence 16,18, 20, 22, 24,..............should be taken to get an average 100 ?

Question

Hemant sold 10 sarees for a total profit of Rs. 460 and 12 sarees for total profit of Rs. 144.
At what profit per saree should he sell the remaining 20 sarees so that he gets an average profit of Rs. 18 per saree?

Answer 1

There are 85 numbers total

Average = sum of n numbers divided by n.

Sum Of n numbers = n/2(2a+(n-1)d)
ie= 85/2(2*16+(84)2)
= 85/2(32+168)
= 85/2(200) =8500.

Average =8500/85
ie=100.

So the answer is 85