Lookingfor700GMAT wrote:Is the hundreths digit of the decimal D greater than 5?
(1) The tenths digit of 10d is 7
(2) The thousandths digit of d/10 is 7
What exactly is the question asking? I am unusure as digits is a weak part of my game.
Hi,
Let's look at a sample number:
1234.567
"digit" simply means a number between 0 and 9 that holds a place in a bigger number.
The digit immediately to the left of the decimal is known as the "ones" or "units" digit.
The digit to the left of that is the tens digit. Continuing to the left we have the hundreds, thousands and so on digits.
The digit immediately to the right of the decimal is the tenths digit; proceeding to the right we have the hundredths, thousandths and so on digits.
So, in our sample number:
1 = 1000s digit
2 = 100s digit
3 = 10s digit
4 = ones/units digit
5 = 10ths digit
6 = 100ths digit
7 = 1000ths digit
Now let's look at the question you posted:
Is the hundreths digit of the decimal D greater than 5?
(1) The tenths digit of 10d is 7
(2) The thousandths digit of d/10 is 7
So, rephrasing, the question, is the digit two to the right of the decimal in our number D > 5?
Now let's evaluate the statements:
(1) the digit one to the right of the decimal in 10D is 7.
If we let 10D = 1.74 (only the 7 matters),
then D = 1.74/10 = .174.
The 100s digit of D is 7. Is 7 > 5? YES!
Since we had to pick 7 in that spot, we'll always get 7 no matter how we change the other digits: sufficient.
(2) the digit three to the right of the decimal in D/10 is 7.
If we let D/10 = 1.237 (again, only the 7 matters),
then D = 10 * 1.237 = 12.37.
The 100s digit of D is 7. Is 7 > 5? YES!
Again, since we had to pick 7 in that spot, we'll always get 7 no matter how we change the other digits: sufficient.
Each statement is sufficient by itself, choose (D).
