eighteen years ago , a father was 3 times as old as his son . now the father is only twice as old his son . then the sum of the present ages of the son and the father is :
explanation : let the present ages of the father and son be 2 x and x years respectively . then , ( 2 x - 18 ) = 3 ( x - 18 ) = > x = 36 required sum = ( 2 x + x ) = 108 years . answer : option d
add(subtract(multiply(multiply(add(const_3, const_3), 3), 3), multiply(add(const_3, const_3), 3)), multiply(subtract(multiply(multiply(add(const_3, const_3), 3), 3), multiply(add(const_3, const_3), 3)), const_2))