In the number 0.58d6 what number does the digit d represent?

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AAPL: Moderator; Posts: 2599; Joined: Sun Oct 29, 2017 2:08 pm; Followed by:2 members

In the number 0.58d6 what number does the digit d represent?

by AAPL » Fri Nov 03, 2017 7:31 am

In the number 0.58d6 what number does the digit d represent?

(1) If the number 0.58d6 were rounded to the nearest hundredth the result would be 0.59

(2) If the number 0.58d6 were rounded to the nearest thousandth the result would be 0.586.

The OA is B.

I need help with this DS question. Please can any expert explain it for me? Thanks.

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Source: Beat The GMAT — Data Sufficiency | Fri Nov 03, 2017 7:31 am

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ErikaPrepScholar: Legendary Member; Posts: 503; Joined: Thu Jul 20, 2017 9:03 am; Thanked: 86 times; Followed by:15 members; GMAT Score:770

by ErikaPrepScholar » Tue Nov 07, 2017 9:32 am

To round a number, we look at the digit to the right of the digit we are rounding. If it is less than 5, we keep our digit the same. If it is greater than or equal to 5, we increase our digit by 1. So 1.24 rounded to the nearest tenth is 1.2, but 1.25 rounded to the nearest tenth is 1.3.

Statement 1

For the tenths place to round up from 8 to 9, the hundredths place (the digit to the right of the tenths place) must be greater than or equal to 5. This means d could equal 5, 6, 7, 8, or 9. Insufficient.

Statement 2

Since the thousands place (the digit to the right of the hundreds place) is 6 (which is greater than or equal to 5), the hundreds place must have been rounded up from 5 to 6. This means d equals 5. Sufficient.