Present ages of Richa and her husband are in ratio 3 : 4. Five years from now, ages of her husband and her son will be in ratio 3 : 1. If the present age of Richa is 21 years, then what will be her son’s present age (in years)?

Let Richa's present age = $$3x$$ years and her husband's present age = $$4x$$ years

Also, present age of Richa = 21 years

=> $$3x=21$$

=> $$x=\frac{21}{3}=7$$ years

Thus, her husband's present age =$$4\times7=28$$ years

5 years from now, let her husband's age = $$3z$$ years and her son's age = $$z$$ years

Her husband's age 5 years from now = $$28+5=33$$ years

=> $$3z=33$$

=> $$z=\frac{33}{3}=11$$

$$\therefore$$ Son's present age = $$z-5=11-5=6$$ years

=> Ans - (C)