Six years back, a father was 42 years older than his son. At present the father is 4 times as old as the son. How old will the son be three years from now?	Choose the correct choice from the following:
A) 20 years
B) 19 years
C) 18 years
D) 17 years
E) 16 years
Using linear equations to convert the word problem:   ** F = fathers current ageS = sons current age   #1 Six years back, a father was 42 years older than his son: F-6 = 42 + (S - 6)   #2 At present the father is 4 times as old as the son: F = 4*S   How old will the son be three years from now?: S + 3 = ?   With two variables and two linear equations we are able to solve the problem:   (S*4) - 6 = 42 +S -6   3S=42   S = 14   S + 3 = 14 + 3= 
<gadget id="calculator">14 + 3</gadget>
<output>17</output>
17   Answer: 17 years
<result>D</result>
Six years back, a father was 42 years older than his son. At present the father is 4 times as old as the son. How old will the son be three years from now?