Source: Official Guide for GMAT Review 2016 Data Sufficiency ; #64

1

# From May 1 to May 30 in the

From May 1 to May 30 in the same year, the balance in a checking account increased. What was the balance in the checking account on May 30?

### 1 Explanation

1

Danny Watts Jr

It would be helpful to use the compound interest formula for this: A = P(1+n/r)^(nt). We want to solve for A.

1: Writing this out as a formula makes it look like it's solvable: 504 = P(1+.12)^1. However, this statement is a hypothetical. We aren't given the actual interest rate needed to solve this problem. We are given the initial principal amount (\$450), though, which can be useful for later. NOT SUFFICIENT
2: NOT SUFFICIENT since it doesn't give us any actual amounts.
Combined: We know the principal amount (\$450) and the rate increase (8% or 1.08), so we can solve for the answer. Answer = C.

Nov 25, 2017 • Comment

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