In How many Years will the Amount become 16 Times
Answer: (b) 16 years
Given that, Invest amount is doubled in = 4 years,
So after 4 years base amount will be twice of initial amount. After next 4 year (total 8 years) total amount will become 4 times and for next 4 years this amount will be the base amount and so on.
Therefore, Amount will be four times in 8 years;
and amount will be 4*2 =8 times in 12 years;
and 8*2 = 16 times in 16 years.