What type of math is this?

25% of what is 30?
and
solve for a: ab=b=3a-d

5 answers

Your first problem is a percentage problem. 25% = 0.25
0.25 * 30 = 7.5
your doing "is over of equals percnt over 100. so you set it up

30/x =25/100
cross multiply and solve for x

25x= 3000

dicide by 25 for your answer.

this is stuff you learn in algebra. i am confused with the second equation though
But the answer is 120. I have the answers to those questions. I just need to know topics they are included in so I can study.
correction
ab+b=3a-d
Oops, Alex, I misread your problem. I'm sorry.

25% of what is 30
0.25x = 30
x = 30/0.25
x = 120