Alternative solution:
Statement 1: start with 50 to 59
ranges from 10/50 to 10/60 (approximate the 59 to 60)... thats 20% down to 16.67%. thats a close number - rough and dirty 10/59 you can confirm will mean that there is
ATLEAST one combination out there where its less than 17%. mere existence is enough is say this is
Insufficient. Till here maybe 30s
Left with B, C, or E
Statement 2:
squarely puts it in the 8-handle region.
at the top of the Range 16/80 is 20% at the bottom 16/90
learn the aproximation for 1/9 which is 11.11%
so 1/90 will be 1.11%
1.1*16 is 17.6% (this is the 11x trick)... meaning 16/89
has to be higher than 17%. great. which means the 8-handle numbers are
universally greater than 17%. Sufficient. Answer is B.
Another way to double confirm is to do [16][/89] > 17/100 rewrite 89 as 100-11 and cross multiply.
\frac{16}{100-11 } > \frac{17}{100}
1600 > 1700 - 187 (this is 11x mental maths you should know)
dont bother solving. 1600 is 100 less than 1700. but RHS is 187 less that LHS. therefore 1600 is bigger... or whatever short cut you use. All this to confirm that \frac{16}{89 }is indeed > 17%
Let me know what you think.
Bunuel