<p>Can someone help explain it to me? for some reason im not understanding it... </p>
<p>If a, b, and c are numbers such that a over b = 3 and b over c = 7, then (a+b) over (b+c) is equal to which of the following?
A. click to choose answer A 7 over 2
B. click to choose answer B 7 over 8
C. click to choose answer C 3 over 7
D. click to choose answer D 1 over 7
E. click to choose answer E 21</p>
<p>let a = 21, b= 7 (a/b , 21/7 = 3)
let b=7, c=1 (b/c, 7/1 = 7)</p>
<p>a + b/b + c</p>
<p>21 + 7 / 7 + 1</p>
<p>28/8</p>
<p>7/2</p>
<p>fail…wow that was easy. is that the only way to solve by plugging in or is there an algebraic way?</p>
<p>there is another way, I just found that way simple, here is the other:</p>
<p>someone else in another thread about the same question posted this:</p>
<p>a/b = 3 & b/c = 7 </p>
<p>now b = 7c. Plug that back in for b in a/b = 3.</p>
<p>a/7c = 3
a = 21c</p>
<p>now we have
a = 21c
b = 7c
and c </p>
<p>just subsitute the values
a+b/b+c </p>
<p>21c + 7c/ 7c + c </p>
<p>= 28c/8c</p>
<p>which = 7/2 cause the c’s cancel out.</p>
<p>simple and effective. takes no more than 20-30 seconds.</p>