What will come in the place of question mark (?) in the following question.

? × 15 + 30% of 400 = 8×30

A number, when increased by 60%, gives 3590. The number is:​

If 4% of x = 96, then x is equal to:

By how much is 65% of 65 greater than 1/5 of 15?

If 4% of x = 48, then x is equal to:

If 4% of x = 36, then x is equal to:

If 2% of x = 312, then x is equal to: