Direction : What value should come in the place of question mark (?) in the following questions?

283 ÷25x4 + 186 = ? 

If 999x + 888y = 1332 and 888 x + 999y = 555.then the value of (x + y) is-

Direction : What value should come in the place of question mark (?) in the following questions?

$${210\over14}×{17\over15}×?=4096  $$

4⁶¹ + 4⁶² + 4⁶³ + 4⁶⁴ is divisible by: 

0.8% of a number is 31, then find the number.

A is inversely proportional to square of B whereas directly proportional to C. Value of A was 27 when value of B was 4 and value of C was 6. Find the value of A when value of B will be 3 and value of C will be 8.

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

√(?) + 15² = 235

The sum of four numbers is 64. If we add 3 to the first number, 3 is subtracted from the second number, the third is multiplied by 3 and the fourth is divided by 3, then all the results are equal. What is the difference between the largest and the smallest of the original number?