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

68 x ? - 3421 = 591

If x + y = 12 and xy = 32, then what is the value of  x2 + y2 ?

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

?2% of 650 = 202 + 42

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

52x14+145018=1998÷?

What should come at the place of question mark (?) in the following question?

437+216-413=?-234

If 2x + 3(5-2x) > 2 - 3x < 2x - x/3, then x can take which of the following values?

Simple interest on a certain sum of money for 3 years at 8% per annum is half the compound interest on Rs 1200 for 2 years at 10% per annum. The sum placed on simple interest is

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

325-122+75=?2-68