40% read Newspaper X and 50% read Newspaper Y. If 10% read both, what percentage read neither newspaper?

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 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?

In an exam, 70% candidates passed in physics and 80% candidates passed in reasoning. If 55% passed in both, what percent failed in both subjects?

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