BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

What is the hundredths digit of th decimal Z?

Expert replies
by BTGmoderatorDC » Thu Aug 02, 2018 5:39 pm

Timer

00:00

Answers

A

B

C

D

E

Stats

Difficulty

What is the hundredths digit of th decimal Z?

(1) The tenths digit of 100z is 2
(2) The units digit of 1,000z is 2

OA E

Source: GMAT Prep
Join the discussion
Source: — Data Sufficiency |

by GMATGuruNY » Thu Aug 02, 2018 7:44 pm
BTGmoderatorDC wrote:What is the hundredths digit of the decimal Z?

(1) The tenths digit of 100z is 2
(2) The units digit of 1,000z is 2
Statement 1:
100z = 0.2, 1.2, 2.2...
Dividing every value by 100, we get the following options for z:
z = 0.002, 0.012, 0.022...
Since the hundredth digit of z can be different values, INSUFFICIENT.

Every value in the blue list above also satisfies Statement 2.
Thus -- even when the statements are combined -- the hundredth digit of z can be different values.

The correct answer is E.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Join the discussion

by Brent@GMATPrepNow » Fri Aug 03, 2018 6:02 am
BTGmoderatorDC wrote:What is the hundredths digit of th decimal Z?

(1) The tenths digit of 100z is 2
(2) The units digit of 1,000z is 2

OA E

Source: GMAT Prep
Target question: What is the hundredths digit of the decimal z?

Statement 1: The tenths digit of 100z is 2
Notice what happens when we take a decimal like 0.123456 and multiply it by 100.
We get 12.345 (the tenths digit is 3)
In the original decimal, the 3 was in the thousandths place.
So, statement 1 tells us that the THOUSANDTHS digit of z is 3
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: The unit digit of 1000z is 2
Notice what happens when we take a decimal like 0.123456 and multiply it by 1000.
We get 123.45 (the units digit is 3)
In the original decimal, the 3 was in the thousandths place.
So, statement 2 tells us that the THOUSANDTHS digit of z is 3
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

NOTE: Since statements 1 and 2 BOTH tell us the same thing (i.e., the THOUSANDTHS digit of z is 3), the combined statements are NOT SUFFICIENT

Answer: E

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Join the discussion