Jacob's age 18 years hence will be thrice his age four years ago. Find Jacob's present age?  Choose the correct option.
A) 16  B) 20  C) 15  D) 11  E) 16
C   15   Let Jacob's present age be 'm' years.   m + 18 = 3(m - 4)   =&gt; 2m = 30 =&gt; m = 15 years.
<result>C</result>
Jacob's age 18 years hence will be thrice his age four years ago. Find Jacob's present age?