A's weight is 25% of B's weight and 40% of C's weight. What percentage of C's weight is B's weight?

If 40% of an amount is 250, what will be 60% of that amount?

If 30% of P is added to 40% of Q, it becomes 80% of Q. Accordingly, what is the percentage of Q with respect to P?

A number is increased by 20% and then decreased by 20%. Net increase/decrease percentage?

A number is mistakenly divided by 4 instead of multiplied by 4. What is the percentage change in the result?

A student scored 65% marks in an exam. If he scored 78%, 70%, 62% and 65% marks in four subjects out of five subjects, then what is his percentage of marks in the fifth subject?