<p>For those of you that have the test here it is lol.
It sucks that they dont' offer answer explanations for old tests but anyawys.. for secton 2 how do you questions 17 and 18?</p>
<p>nvmd question 20 lol i got 17 and 18 when i do it on paper :P</p>
<p>how do you question 20 other than guess and checking… like making a list of the digits
so for k=0 choice
j=9 k=0 and n=1
This is since j is less than k but j is a two -digit number cuz single digit integers don’t provide a 9 as units other than 7x7. so yeah the next digit less than say “20” is 19 which is the consecutive integer before 20 which has 9 as a units. 0 is the answer but is there another way of doing this other than listing the digits out? Don’t get me wrong this method is actually pretty fast and if you’re like me and start at A instead of C like you’re supposed to lol you get it on the first try so this problem takes 10-20 seconds if you figure out what to do.</p>
<p>I think the only way to solve it would be to know that j has to be 1 digit column less than n.</p>
<p>Ex.</p>
<p>j = 9
k = 10
n = 11</p>
<p>jn = 99</p>
<p>j = 99
k = 100
n = 101</p>
<p>jn = 9999</p>
<p>Therefore, it’s choice A) because the ones digit of k must always be 0.</p>