Samad's age and his father's age are 12 years old and 40 years old
respectively. How many years later
will Samad's father be twice as old as
Samad?

Step-by-step explanation:

let x= time period in years between age now and when  father's age=2* the samad's age

in x years father's age will be 40 + x years old

in x years samad's age will be 12+x years old

at a certain point in time, the father's age = 2*the samad's age

40+x=2*(12+x)

or, 40 +x=24 + 2x

or, 40-24 = x

   x=16

test:

father=40+16=56

son=12+16=28

hence , after 16 years samad's father will be twice as old as samad