15 of 200

15 of 200 is 30

Here is the best way to calculate:

Unknown value "Y"
100% / 200 = 15% / Y
100 / 200 = 15 / Y
Y ( 100 / 200 ) = 15
Y = 15 ( 200 / 100 )

The Answer: Y = 30

Source: https://percentage-calculator.net/what-is-x-percent-of-y/what-is-15-percent-of-200.php