Quantitative Aptitude - Arithmetic Ability Questions

What approximate value should come in place of the question mark (?) in the following equation (Note: You are not expected to calculate the exact value)? 499.99 + 1999 ÷ 39.99 × 50.01=?

The value of -261+(-380)-(-521)+821-(-121)

If 3x^2 + ax + 4 is perectly divisible by x - 5, then the value of a is :

Solve the following : 3/4+{3/4 + 3/4 ÷ (3/4 + 3/4)} = ?

Solve the following: (−18)[36÷7−(−2)]÷{}(−4)19−(−3)×(−5)={}?

If the value of √42 is approximately 6.480, then what is the approximate value of √(6/7)?

What is the value of [12/(√5 + √3)] + [18/(√5 – √3)]?

If the value of 3-1.732, then calculate the value of 243-12108-147