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Let's say \(z=a.bcd\). The hundredths digit of z would be the value of \(c\). So the question is \(c=?\)

(1) The tenths digit is 100z is 2 --> \(100z=100*a.bcd=abc.d\) --> the tenths digit of \(100z\) is the value of \(d\). So \(d=2\). Not sufficient to calculate \(c\).

(2) The units digit of 1,000z is 2 --> \(1000z=1000*a.bcd=abcd\) --> the units digit of \(1000z\) is the value of \(d\). So \(d=2\). Not sufficient to calculate \(c\).

(1)+(2) No new info, only the value of \(d\) is known. Not sufficient.

I am sure Bunuel's explanation should have cleared your doubts, if there was any. But I pretty much followed the same what Bunuel explained.

Z = A.bcde

From stem, we should be able to find the value of 'c'

1. 100Z = A.bcde * 100 = Abc.de => tenth digit of 100z = d = 2, Not Sufficient to find the value of C 2. 100Z = A.bcde * 1000 = Abcd.e => units digit of 1000Z = d = 2, Not Sufficient to find the value of C

Both 1 and 2 are talking about 1000th digit of Z, which is Z. Hence, together 1 and 2, as well, we can not find the value of 100th digit of Z.

Let's say \(z=a.bcd\). The hundredths digit would be the value of \(c\). So the question is \(c=?\)

(1) The tenths digit is 100z is 2 --> \(100z=100*a.bcd=abc.d\) --> the tenths digit of \(100z\) is the value of \(d\). So \(d=2\). Not sufficient to calculate \(c\).

(2) The units digit of 1,000z is 2 --> \(1000z=1000*a.bcd=abcd\) --> the units digit of \(1000z\) is the value of \(d\). So \(d=2\). Not sufficient to calculate \(c\).

(1)+(2) No new info, only the value of \(d\) is known. Not sufficient.

Answer: E.

When the question asks hundredths digit of the decimal z? , in that case, for example, \(z=xyz.bcd\)

x = hundredth digit c = hundredth digit

How did you assume that the question is asking for C and not for X?

Re: Please help!! Difficult problems from GMATPrep [#permalink]

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14 Sep 2010, 20:00

3. What is the hundredths digit of the decimal z?

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

Let the number, z be x.abcde. We need to find the hundredths digit of the decimal z which is the value of b. Statement 1: 100z = xab.cde Given the tenth digit of 100z is 2 and hence c is 2.

Statement 2: 100z = xab.cde. Given the units digits of 100z is 2 and hence b is 2.

Statement 2 is alone sufficient to answer this question. Answer B.
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Re: What is the hundredths digit of the decimal z? [#permalink]

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12 Jan 2014, 07:06

If it is asking for what is the hundredths digit of decimal z, isn't z just a digit between 0-9? In that case, isn't isn't any other digit besides the units digit of z=0? e.g. z= 09.00?

Let's say \(z=a.bcd\). The hundredths digit of z would be the value of \(c\). So the question is \(c=?\)

(1) The tenths digit is 100z is 2 --> \(100z=100*a.bcd=abc.d\) --> the tenths digit of \(100z\) is the value of \(d\). So \(d=2\). Not sufficient to calculate \(c\).

(2) The units digit of 1,000z is 2 --> \(1000z=1000*a.bcd=abcd\) --> the units digit of \(1000z\) is the value of \(d\). So \(d=2\). Not sufficient to calculate \(c\).

(1)+(2) No new info, only the value of \(d\) is known. Not sufficient.

Let's say \(z=a.bcd\). The hundredths digit of z would be the value of \(c\). So the question is \(c=?\)

(1) The tenths digit is 100z is 2 --> \(100z=100*a.bcd=abc.d\) --> the tenths digit of \(100z\) is the value of \(d\). So \(d=2\). Not sufficient to calculate \(c\).

(2) The units digit of 1,000z is 2 --> \(1000z=1000*a.bcd=abcd\) --> the units digit of \(1000z\) is the value of \(d\). So \(d=2\). Not sufficient to calculate \(c\).

(1)+(2) No new info, only the value of \(d\) is known. Not sufficient.

Think I may just not understand what a decimal is. Why is decimal z not just a number from 0-9? Decimal z ≠ a digit?

Let's say \(z=a.bcd\). The hundredths digit of z would be the value of \(c\). So the question is \(c=?\)

(1) The tenths digit is 100z is 2 --> \(100z=100*a.bcd=abc.d\) --> the tenths digit of \(100z\) is the value of \(d\). So \(d=2\). Not sufficient to calculate \(c\).

(2) The units digit of 1,000z is 2 --> \(1000z=1000*a.bcd=abcd\) --> the units digit of \(1000z\) is the value of \(d\). So \(d=2\). Not sufficient to calculate \(c\).

(1)+(2) No new info, only the value of \(d\) is known. Not sufficient.

Think I may just not understand what a decimal is. Why is decimal z not just a number from 0-9? Decimal z ≠ a digit?

I think you should brush up fundamentals. Decimals and digits are not the same thing.

Decimal is a numbers that fall in between integers and expressed in terms of place value. For example, 3.4 , 1.7777, 7.8, ... are all decimals.

While digits are numbers 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

Re: What is the hundredths digit of the decimal z? [#permalink]

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19 Nov 2016, 01:46

let z=abc.pqr we need q statement 1 100z=abcpq.r tenths =r=2 no clue of q=> not sufficient statement 2 1000z=abcpqr units =r hence r=2 no clue of q => not sufficient combining the two statements we get r=2 still no clue of q hence E
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(1) The tenths digit is 100z is 2 (2) The units digit of 1,000z is 2

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 2 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 2 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 2), the combined statements are NOT SUFFICIENT