Answer:
$84.50
Step-by-step explanation:
So percent means parts out of 100 so 75%=75/100=3/4
3/4 of 30
'of' means multiply
3/4 times 30=90/4=45/2=22.5
22.5 is the answer (or 22 and 1/2)

notice, it goes 4,6 then 4, 6 again, and so on and so on
based on whatever exponent it may have
now, you're being asked, what 214 will give? 4 or 6?
Just invert it like:

There you have your common denominator! Don't forget to multiply the numerator as well.