Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

John invest $2,000 at a constant interest rate of annually compound 5%. If the amount from the investment after n years is p, p=(2,000)1.05^n, is n>4?

1) p>2,100

2) p<3,000

In the original condition, there is 1 variable, which should match with the number of equations. For 1) 1 equation, for 2) 1 equation, which is likely to make D the answer.

Howver, 1) 2,000(1.05^4)=2,430 -> no, 2,000(1.05^5)=2,551 -> yes

2) 2,000(1.05^4)=2,430 -> no, 2,000(1.05^5)=2,551 -> yes

1) & 2) 2,000(1.05^4)=2,430 -> no, 2,000(1.05^5)=2,551 -> yes

The final answer is E

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