Bunuel
Is \(\frac{x + 1}{y + 1} > \frac{x}{y}\)?
(1) \(0 < x < y\)
(2) \(xy > 0\)
(DS09315)
The question can be solved without putting pen to paper in 30 secs using number properties.
Is \(\frac{x + 1}{y + 1} > \frac{x}{y}\)?
Recall that when we add the same positive number to both the numerator and denominator of a positive fraction, it moves towards 1.
(1) \(0 < x < y\) x and y both are positive so x/y is positive and less than 1. When we add 1 to both x and y, the fraction obtained (x+1)/(y+1) will be closer to 1 and hence will be greater than x/y. Imagine them on the number line:
-------------------- 0 ----------- x/y------x+1/y+1-------------1-----------
Hence, (x+1)/(y+1) is greater than x/y and we can answer the question with a 'Yes'. Sufficient alone.
(2) \(xy > 0\)We don't know whether x and y are positive or negative. Also we don't know whether x/y is less than 1 or greater than 1 even if they are both positive.
Not sufficient.
Answer (A)