math
posted by Alex on .
What type of math is this?
25% of what is 30?
and
solve for a: ab=b=3ad

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=3ad 
Oops, Alex, I misread your problem. I'm sorry.
25% of what is 30
0.25x = 30
x = 30/0.25
x = 120