Data Sufficiency

In the xy-plane, what is the y-intercept of line L?

(1) The slope of line L is 3 times its y-intercept?
(2) The x-intercept of line L is (-1/3)



Needed a simpler solution.thanks !!



SPOILER:





E

Let us consider the line
y= mx + c
y intercept => means X= 0 in the equation=> Y=C ---Equation A?
statement 1:

Slope = 3 * y intercept => m=3C--- Equation B
Two unknown constant m and C so it is not suff.

Not sufficient

Statement 2:
X intercept => y=0 in the equation => mX + c = 0 =>
X= -c/m-- Equation C
Again two unknown constants so not sufficient

Combine 1 and 2
Since we cannot use Equation B and Equation C to solve Equation A
SO Ans E

aj5105 wrote:In the xy-plane, what is the y-intercept of line L?

(1) The slope of line L is 3 times its y-intercept?
(2) The x-intercept of line L is (-1/3)



Needed a simpler solution.thanks !!



SPOILER:





E

Stem:Y intercept hence X=0 ( lets say y2=?, x2=0)

1. M=3 y2

2. Slope=M=(y2-y1)/(x2-x1)

x1=-1/3; y1=0..... from statement 2 ( X intercept is -1/3 means Y=0)

From stem, X2=0

hence solving the equation,M=3y2

Means Statment 1=2

In such situations, its as good as you have one equation hence E


Take aways:

Always simplify statements; Fortunately, when they are same ans can be D or E so you save lot of time and even if you dont have any clue, you have 50% chances of getting it right