Lets say W=Wesley, M=Max, and J=Jared.
So your equations are M=2J, 2M=W, and M+J+W=21days(3 weeks)
So substituting M and W into M+J+W=21 gives you 2J+J+2M=21, substitute M again, to get 2J+J+4J=21 so you get 7J=21 so J= 3 days. Using J=3, substitute in to find M, using M=2J, so M=2(3) so M=6 and using that, substitute into 2M=W, so 2(6)=W so W=12. And 12+6+3=21 to check.
Let <em>x</em> be the amount of salt in the solution.
At day's end, the concentration of salt in the beaker is
<em>x</em> / (4 L) = 0.08 = 8%
Solve for <em>x</em> to get
<em>x</em> = 0.08 (4 L) = 0.32 L
So at the beginning, the concentration of salt in the beaker was
(0.32 L) / (5 L) = 0.064 = 6.4%
I’m gonna say that the answer is 5: 14
