Direction: what should come in place at question mark(?).

(0.85% of 405) +(2.25% of 550)=?

Direction : What should come in place of the question (?) in the following question.

140% of 450 + 24% of 650 =?

If (x +y) = 6 and x² + y² = 20 then find the value of (x - y) ².

Direction : What should come in place of the question (?) in the following question.

(47 × 588) ÷ ( 28 × 120)=?

Direction : What should come in place of the question (?) in the following question.

(41) ² + (38)² × (0.15)²=?

Simplify the following equation.
$${(785.785.785+435.435.435) \over(785)^{2}+(435)^{2}-(785)(435)}$$

If 0.5x + 0.7y=0.5 and 0.7x + 0.5y=0.7,then the value of x+y is

How many perfect squares lie between 120 and 300?