In a survey of 100 students, the number of students studying the various languages was found to be: English only 18, English but not Hindi 23, English and Sanskrit 8, English 26, Sanskrit 48, Sanskrit and Hindi 8, no language 24. Find:

How many students were studying English and Hindi?

In a survey of 100 persons, it was found that 28 read magazine A, 30 read magazine B, 42 read magazine C, 8 read magazines A and B, 10 read magazines A and C, 5 read magazines B and C and 3 read all the three magazines. Find:

How many read magazine C only?

In a survey of 100 students, the number of students studying the various languages was found to be: English only 18, English but not Hindi 23, English and Sanskrit 8, English 26, Sanskrit 48, Sanskrit and Hindi 8, no language 24. Find:

How many students were studying Hindi?

In a survey it was found that 21 persons liked product P₁, 26 liked product P₂ and 29 liked product P₃. If 14 persons liked products P₁ and P₂; 12 persons liked product P₃ and P₁; 14 persons liked products P_2, and P₃ and 8 liked all the three products. Find how many liked product P₃ only.

If a set contains n elements, then write the number of elements in its power set.