Consider the following addition problem : $3P + 4P + PP + PP = RQ2$; where P, Q and R are different digits. What is the arithmetic mean of all such possible sums?

Integers are listed from 700 to 1000. In how many integers is the sum of the digits 10?

Consider the following multiplication problem:

$(PQ) \times 3 = RQQ$, where P, Q and R are different digits and $R e 0$.

What is the value of $(P+R) \div Q$?

A biology class at high school predicted that a local population of animals will double in size every 12 years. The population at the beginning of the year 2021 was estimated to be 50 animals. If P represents the population after n years, then which one of the following equations represents the model of the class for the population?

The difference between a 2-digit number and the number obtained by interchanging the positions of the digits is 54.

Consider the following statements:

1. The sum of the two digits of the number can be determined only if the product of the two digits is known.
2. The difference between the two digits of the number can be determined.

Which of the above statements is/are correct?

A student appeared in 6 papers. The maximum marks are the same for each paper. His marks in these papers are in the proportion $5 : 6 : 7 : 8 : 9 : 10$. Overall he scored 60%. In how many number of papers did he score less than 60% of the maximum marks?