A number of illerate person in a country decrease from $150$ lakh to $100$ lakh in $10$ years. What is the percentage of decrease.

According to the question,

Required percentage $=\frac{150-100}{150}\times 100$

Required percentage $=\frac{50}{150}\times 100$

Required percentage $=\frac{1}{3}\times 100$

Required percentage $=33.33\%$

Hence, this is the answer.