Question

1. A chemistry student needs to make a solution that is 70% water and 30% hydrochloric acid. The student's current mixture of 300 ml is 60% water and 40% hydrochloric acid. How much water must the student add to achieve his desired solution?

A: ?

2. 5. 2/t + 4/3t = 4/t + 2

A: t = 10?

Answer 1

did that for you here
http://www.jiskha.com/display.cgi?id=1401816411

#2, was also done somewhere, can't find it, so ...

The way you typed it:
2/t + 4/3t = 4/t + 2
times 3t

6 + 4t^2 = 12 + 6t
4^2 - 6t - 6 = 0
2t^2 - 3t - 3 = 0
t = (3 ± √33)/4
somehow I don't think that is what you meant, you must have meant:

2/t + 4/(3t) = 4/t + 2
times 3t
6 + 4 = 12 + 6t
-2 = 6t
t = -1/3

or did you mean:
2/t + 4/(3t) = 4/(t+2) ????

Also where does the 5 at the beginning fit in?