Would this even be a GMAT question Since it requires knowledge of the normal distribution and standard deviation's relation in normal distributions?

http://www.regentsprep.org/Regents/math ... Lesson.htm

So imagine a line with point A--------------------B and will say the distance between them 120 miles. We will assume Ad=0 miles and Bd=120 miles. imagine the 90 mph trains leave point B at t=0 and the 30 mile per hour train leaves point A at t=0 so at t=1 hour A is at the 30 mile marker and B is als...

This one took a bit so I def would have had to skip it on the GMAT or guess but I solved it like this.. RR=rate of R RA=rate of A so we know that in 8 hours (2 hours to catch up plus 6 to meet back up) R went 90 + (90-distance A already went) distance A went = rate * time =RA*9 (he left an hour befo...

For me it was easy to see that it wouldn't always be greater by just picking numbers and plugging them into your simplified statement

say x=y=(1/2)

(2x)^10=(2(1/2))^10=1
2x=2(1/2)=1

Therefore in every case it will not be greater than the (X+Y)^-5

from observation you know that arc OP will equal arc QR. If we can find those length we can subtract them from half of the circumference and find the arc PQ so arc OP = 2(pi)(9)(70/360)=7/2 (pi) double the 35 arc OP+arc QR = 2 arc OP= 14/2 (pi)=7 pi half the circumference of the entire circle is (18...

I tried to think of this in terms of inequalities. saw k=ABC (1) tells us ABC + 9 =A3C (i know its not really c any more since 4 was added but who cares) it can only be three if the following inequality is met A21<=ABC<=A31 (so the ten's digit could be 2 or 3, but wait! the units digit is non zero s...