Quantitative Aptitude - Arithmetic Ability Questions

What approximate value should come in place of the question mark (?) in the following questions? (You are not expected to calculate the exact value.)

21.003 × 39.998 –209.91 = 126× ?

Find the odd word/letters/number from the given alternatives.

Choose the odd word/letters/number/number pair from the given alternatives.

One of the diagonal of a rhombus is 70% of the other diagonal. What is the ratio of area of rhombus to the square of the length of the larger diagonal?

The flight fare between two cities is increased in the ratio 9:11. What is the increase (in Rs) in the fare, if the original fare was Rs. 18,000?

If (X/4) = (Y/5) = (Z/9), then what is X : Y : Z?

If x = 6+26, then what is the value of x-1 + 1x-1 ?

In the following question, four number pairs are given. The number on left side of (–) is related to the number on the right side of (–) with some Logic/Rule/Relation. Three are similar on basis of same Logic/Rule/Relation. Select the odd one out from the given options.