Before 5 years, dog A’s age was 4 times of dog B’s age and after 4 years, dog A’s age will be 3 times of dog B’s age. What is the difference of dog A’s age and dog B’s now?
Pick
A) 36 B) 42 C) 58 D) 60 E) 64
A - 5 = 4(B - 5) --&gt; A - 4B = -15.............1   A + 4 = 3(B + 4) --&gt; A - 3B = 8.............2   (2) - (1) --&gt; B = 23 --&gt; A =3(27)=81   A - B = 81 - 23= 
<gadget id="calculator">81 - 23</gadget>
<output>58</output>
58   Answer: 58
<result>C</result>
Before 5 years, dog A’s age was 4 times of dog B’s age and after 4 years, dog A’s age will be 3 times of dog B’s age. What is the difference of dog A’s age and dog B’s now?