.Find 30% of 600 and Find10% of 500 and 20 is what precent of 400 and 187.2 is 36% of what?

so first think that whenever you see "of" it means multiply, and whenever you see "is" or "equals to" is means "="

1) 30% of 600
= .3 x 600
= 180
2) 10% of 500
= .1 x 500
= 50
3) 20 is what % of 400
20 = y "times" 400
20/400 = y
y = 1/20
y = 5%
4) 187.2 is 36% of what
187.2 = .36 "times" y
y = 187.2/.36
y = 520