Question

A sequence of numbers is given by the formula an= 2(-1.2)^n, where n is a positive integer. What is the probability that a randomly chosen term from the first 3 terms will be negative?

A. 1/3

b. 1/2 C. 2/3 D. 0

Answer 1

2 / 3

Explanation:

Given the formula :

an= 2(-1.2)^n

At n = 1

a(1) = 2(-1.2)^1 = 2(-1.2) = - 2.4

At n = 2

a(2) = 2(-1.2)^2 = 2(-1.2)^2 ; 2 * 1.44 = 2.88

At n = 3

a(3) = 2(-1.2)^3 = 2(−1.728) ; 2 * - 1.728 = - 3.456

Number of negative numbers from first three term = 2

P(choosing a negative term) =

Number of negative numbers from first three term / total number of terms

= 2/3