Which number in the following list does not belong to the group?

If (1/4)*(2/6)*(3/8)*(4/10)...*(31/64) = 1/(4^x), find the value of x.

A man counted his animals, 80 heads and 260 legs (ducks and goats). How many goats are there?

  What is the difference between 1500 and the nearest perfect square number? 

In what proportion must water be mixed with spirit to gain 25% by selling the mixture at cost price?

 In 4 years the simple interest on certain sum of money is 9/25 of the principal. The annual rate of interest is
 

In class, there are 15 boys and 10 girls. Three students are selected at random. The probability that 1 girl and 2 boys are selected, is:

A, B, and C together can earn ₹3,240 in 18 days. A and C can earn ₹1,200 in 10 days, while B and C can earn ₹1,820 in 14 days. Find the daily earnings of C.

 If it is possible to form a word with the first, fourth, seventh and eleventh letters of the word ’SUPERFLUOUS’, Write the first letter of that word. Otherwise, X is the answer. 

A man's monthly salary for a given month is Rs 50,000. His salary is increased by 20% after every 6 months. Find the man's net salary after 1 year.