Permutations an...

Directions for questions 1 to 3: Find the related word/ letters/numbers from given alternatives.
12:72::8:?

If $$12\times 16 = 188$$ and $$14\times 18 = 248$$, then find the value of $$16\times 20 = ?$$

Select the missing number from the given alternatives.

Choose the correct answer from the alternatives given.
If $$1^2+2^2$$ +.... + $$x^2$$ = $$\frac{x(x + 1)(2x + 1)}{6}$$then $$1^2$$ + $$3^2$$+ $$5^2$$ + .... + $$19^2$$ is equal to

How many different $$4$$-person committees can be chosen form the $$100$$ members of the Senate ?

Choose the correct answer alternatives given.
Select the missing number from the given alternatives.

Arrange these numbers in ascending order. 
$$756, 567, 657, 676$$ 

The number of ways in which we can select 5 letters of the word INTERNATIONAL is equal to

The area of the triangle with vertices at $$(-4, 1), (1, 2)(4, -3)$$ is

The area of the triangle whose vertices are (3,8), (-4,2) and (5,-1) is