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Very first thing in this question you should do is to pre-phrase the question. Original question says which is greater, 20 percent of n or 10 percent of the sum of n and 0.5 ? So first numerically denote 20 percent of n and 10 percent of the sum of n and 0.5. 20 percent of n = n*20/100 = 0.2n 10 percent of the sum of n and 0.5 = n*10/100 + 0.5 = .1n + 0.5
We need to see if 0.2n > .1n + 0.5 Or .1n > .5 Or n > 5 (I did not reverse the sign of inequality as all the terms involved are +ve)
Now go to the statements.
Statement 1: Tells us n < 0.1, so n is not greater than 5 and question is answered negatively.
Statement 2: Tells us n > 0.01, but it does not gives us exact value of n. So n can any value less than, more than 5 or even 5 itself. So this statement alone is insufficient.
1) .1>n>0 estimate using boundary conditions: .1*.2=.02 and (.1+.5)*.1=.06 second case larger 0*.2=0 and (0+.5)*.1=.05 second case larger Therefore 10% of (n+.5) I estimate is always larger. Therefore 1 passes
2) n>.01 estimate using boundary conditions (let infinity = 100) (.01)*.2=.002 and (.01+.5)*.1=.051 second case larger (100)*.2=20 and (100+.5)*.1=10.05 first case larger No agreement. Therefore 2 does not pass.