# Jones has worked at Firm X twice as many years as Green

Jones has worked at Firm X twice as many years as Green, and Green has worked at Firm X four years longer than Smith. How many years has Green worked at Firm X?

1. Jones has worked at Firm X 9 years longer than Smith.
2. Green has worked at Firm X 5 years less than Jones.

Assume that the number of years for which Smith has worked for firm X is n.

Therefore, number of years for which Green has worked = (n + 4) years

Number of years for which Jones has worked = 2(n + 4) years

Statement 1: Jones has worked at Firm X 9 years longer than Smith.

In terms of n, 2(n + 4) - n = 9

2n + 8 - n = 9

n = 1

As we can determine the value of n, we can also determine the value of (n + 4). Hence, statement 1 is sufficient to answer the question.

Statement 2: Green has worked at Firm X 5 years less than Jones.

In terms of n, 2(n + 4) - (n + 4) = 5

n + 4 = 5

n = 1

As we can determine the value of n, we can also determine the value of (n + 4). Hence, statement 2 is sufficient to answer the question.

The correct option is D.