solve the following

A. Percentage
a. what is 75% of 800?
(need solution)
b. 500% of 300 is (need solution)

B. Base
a. 90 is 30% of what number (need solution)
b. 45% of what number is 100? (need solution)

C. Rate
a. 28 is what percent of 90? (need solution)
b. what percent if 55 is 5? (need solution)

plsss maayos na sagot po sana pasahan nanamin.
no need to answer kung di Alam​