<p>If 1/a + 1/b = 1/c and ab=c, what is the average of a and b?
(A) 0
(B) ½ (ANSWER)
(C) 1
(D) c/2
(E) a+b/2c</p>
<p>okay so first of all… replace c with ab in the right hand side of the equation, so it becomes
1/a+1/b=1/ab now have a common denominator for the left hand side of the equation by multiplying the denominators and then cross multiply b x 1 and a x 1, it becomes
a+b/ab=1/ab
apparently, a+b=1… so if you want to find an average then divide by two (sum/total)
1/2</p>
<p>If you don’t get this, tell me so I’d write it on a piece of paper, instead.</p>