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× ?

Slope of the side DA of the rectangle ABCD is 5/3. What is the slope of the side AB?

To cover a distance of 225 km in 2.5 hours what should be the average speed of the car in meters/second?

Among three numbers, the first is twice the second and thrice the third. If the average of three numbers is 506, then what is the difference between the first and the third number?

A wholesaler sells a jacket to a retailer at a profit of 5% and the retailer sells it to a customer at a profit of 10%. If the customer pays Rs. 4158, what had it cost (in Rs) to the wholesaler?

In a class of 60 students there are 30 girls. The average weight of these girls is 58 Kg and average weight of the full class is 63 kgs. What is the average weight of the boys of the class?

If A is 6 times more than B, then by what percentage is B is less than A?

If  tan2θ + cot2θ = 2, then what is the value of 2sec θ cosec θ?