y intercept

hi in statement (2) you have x intercept=-1/3 which means when y=0 you have y=-1/3*a+b {y=ax+b <-- equation of line} where a is slope and b is y-intercept, so rewriting gives you 0=-1/3*a+b OR b=a/3 which is the same as statement (1)

statement (1) slope is three times y-intercept --> from y=ax+b {equation of line} write a=3b. This is Not Sufficient, as need to know a slope to answer this question. Slope can be derived if we are given two coordinate points.

Goldfinger2001 wrote:

Hi,

where am I wrong?

Statement1: slope is 3times bigger than y-intercept y=mx+b -> y=3bx + b
Statement 2: x intercept is -1/3

combine both -> -b/3b = -1/3

b=1 -> y intercept = 1 ?

This is a value question, so let's look at what we'd need to determine sufficiency.

y = mx + b

We could find b if we had knew the slope and one coordinate pair, or if we had two coordinate pairs.

(1) y = mx + b
y = 3bx + b

Not suff.

(2) (-1/3, 0) - only gives one coordinate. Not suff.

0 = m(-1/3) + b

COMBINED:

0 = 3b(-1/3) + b

0 = -3b/3 + b

0 = -1b + b

0 = 0

It doesn't give us any new information. The answer is (E).