Direction : What value should come in place question mark(?) in the following questions?

$$2\over7$$ of $$ 5\over6$$ of ?=200

The mean of the first 7 prime numbers is:

The number of pairs of natural numbers the difference of whose squares is 45 will be –

The least number that should be added to 2,397 so that the sum is exactly divisible by 3, 4, 5 and 6 ?

The least number, which must be added to 6709 to make it exactly divisible by 9, is 

When a number is increased by 28, it becomes 107% of itself. What is the number?

Two numbers are respectively 30% and 40% less than a third number. What percent is the first number of the second?

When (6767 +67) is divided by 68, the remainder is-