in 30 years , a will be twice as old as b was 30 years ago . if a is now 5 years older than b , the present age of b is ?
"let b ' s present age = x years then a ' s present age = x + 5 years x + 5 + 30 = 2 ( x - 30 ) x + 35 = 2 x - 60 x = 95 years answer is b"
add(add(multiply(const_2, 30), 30), 5)