karen can read 10 pages and complete 15 math problems in 30 minutes. how long will it take for her to do her homework if she has 30 pages to read and 45 math problems to complete?
If Karen can read 10 pages and complete 15 math problems in 30 minutes, it means she can read 1 page in 3 minutes (30/10=3) and solve 1 math problem in 2 minutes (30/15=2).
Therefore, to read 30 pages, it will take Karen 3 minutes/page * 30 pages = <<3*30=90>>90 minutes.
Similarly, to complete 45 math problems, it will take Karen 2 minutes/problem * 45 problems = <<2*45=90>>90 minutes.
In total, it will take Karen 90 minutes + 90 minutes = <<90+90=180>>180 minutes to complete her homework. Answer: \boxed{180}.