Question

In an old story, a man puts 2 grain of rice on the first space of a chessboard. He puts 4 grains on the third space and so on write and evaluate an expression with exponents to find how many grains of rice the man puts on the tenth space.

Answer 1

Answer: 11

Explanation:

From the question,

a = first term= 2

3rd term = a + 2d = 4

2 + 2d = 4

2d = 4-2

2d = 2

Commons difference = d = 2/2 = 1

10th term = a + (n-1)d = a + (10-1)d = a + 9d

= 2 + 9(1)

= 2 + 9

= 11

The 10th term is 11