If R, S, & T are numbers on the number line, not necessarily in that order, is the value of |R −T| at least 9?

(1) |R − S| = 50.

This tells us that distance between R and S is 50

Nothing about T

Insufficient

(2) |S − T| = 4

This tells us that distance between T and S is 4

Nothing about R

Insufficient

Combined..

Say T is between R and S, then R and T will be 50-4=46 units away

Say T is on other side of S, distance between R and T is 50+4=54

Both cases it is >9 or atleast 9

Sufficient

C

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1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372

2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html

3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html

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