Data Sufficiency

Hi,
Can please tell how to deal with this question:
In the xy-plane, line k has positive slope and x-intercept 4. If the area of the triangle formed by line k and the 2 axes is 12, what is the y-intercept of line k?
-6/-4/-3/3/6
I answered 6 but the correct answer is -6.
I also have difficulties with the following question:
Is the hundredths digit of the decimal d greater than 5?
1) The tenths digit of 10 is 7
2) The thousandths digit of d/10 is 7

Thank you so much for your help.

salma wrote:Hi,
Can please tell how to deal with this question:
In the xy-plane, line k has positive slope and x-intercept 4. If the area of the triangle formed by line k and the 2 axes is 12, what is the y-intercept of line k?
-6/-4/-3/3/6
I answered 6 but the correct answer is -6.

Positive slope means that the line goes from bottom left to top right.

Since the line crosses the x-axis at a positive coordinate (+4), we know that it must cross the y-axis at a negative coordinate.

I line that passed through (0,6) and (4,0) would have a negative slope, so the y-int can't be +6.

* * *

For your second question, I think that there's a "D" missing in one of the statements.

Oh yes thank you.
For the 2nd question it is:
1) The tenths digit of 10d is 7
2) The thousandths digit of d/10 is 7.

Thanks a lot

Salma