Anybody good in math and wanna help me?

Which is the solution to the inequality? 2 3/52 1/15 b< 3 2/15 b> 3 2/15

How many kilograms of a 5% salt solution and how many kilograms of a 15% salt solution must be mixed together to make 45kg of an 8% salt solution?

In the next 10 month,colin wants to save $900 for his vacation.he plans to save $75 each of the first 8 months. how much must he save each of the last 2 months in order to meet his goal if he saves the same amount each month ?