Blog

# The Quest for 700: Weekly GMAT Challenge (Answer)

Yesterday, Manhattan GMAT posted a GMAT question on our blog. Today, they have followed up with the answer:

If you were a computer (or had access to one), you could mechanically take 1.002 to the fourth and then round. However, by hand that would take way too long. The key to this problem is to try a smaller power of 1.002 first.

What is 1.0022? Look at 1.002 as 1 + 0.002. So what is (1 + 0.002)2?

We get (1 + 0.002)(1 + 0.002) = 12 + 0.002×1 + 1×0.002 + 0.0022. Notice that the last term is very, very small: 0.0022 = 0.000004. So we can ignore this part, since we are only going to round to 3 decimal places.

We get (1 + 0.002)(1 + 0.002) ≈ 12 + 0.002×1 + 1×0.002 = 1.004.

Now multiply by another 1.002.

1.004 × 1.002 = (1 + 0.004)(1 + 0.002) = 12 + 0.004×1 + 1×0.002 + 0.004×0.002. Again, we can ignore the last bit, because it’s so small.

1.004 × 1.002 ≈ 12 + 0.004×1 + 1×0.002 = 1.006.

Finally, multiply by one last 1.002, rounding the same way as we go:

1.006 × 1.002 ≈ 12 + 0.006×1 + 1×0.002 = 1.008.

A first-of-its-kind, on-demand MBA application experience that delivers a personalized curriculum for you and leverages interactive tools to guide you through the entire MBA application process.

### Upcoming Events

• Columbia J-Term (Round 2)
• Cambridge Judge (Round 1)
• HBS (Round 1)
• Penn Wharton (Round 1)
• Notre Dame Mendoza (Early Decision)
• Virginia Darden (Early Decision)
• Michigan Ross (Round 1)
• Columbia (Round 1)
• Stanford GSB (Round 1)
• Yale SOM (Round 1)
• Northwestern Kellogg (Round 1)
• Berkeley Haas (Round 1)