Word problem - help Tow teams unleash a container in $20$hrs. If the first team unleash $30\%$ from its part and the second team $20\%$ from its part, they'd unleash $60$ tons together. If the first team unleash $75\%$ from the second team and the second unleash half of the first team part, the first team will finish the job $5$ hours before the second team. 
How many tons per hour each one unleashed?
 A: First of all rewriting your problem: Two teams empty a container in $20$ hrs.  If the first team empty $30\%$ and the second team empty $20\%$, they would empty $60$ tons together.  If the first team did $75\%$ job of the second team and the second team did $50\%$ of the first team, the first team will finish the job $5$ hrs before the second team.  How many tons per hour each team emptied?
Let the time in hours taken by each team be, $t_1$ and $t_2$ respectively $\Rightarrow t_1+t_2=20$...(i)
Let the amount to be emptied in the container is $x$ tons, $0.3x+0.2x=60\Rightarrow 0.5x=60\Rightarrow x=120$ tons.
Let $x_1$ and $x_2$ be the amount in tons they empty respectively $\Rightarrow x_1+x_2=120$...(ii)
So team 1 can empty $\frac{x_1}{t_1}$ tons/hr and team 2 can empty $\frac{x_2}{t_2}$ tons/hr
$\frac{0.75*x_2}{\frac{x_1}{t_1}}+5=\frac{0.5*x_1}{\frac{x_2}{t_2}}$...(iii)
We are asked to find the speed of each team that is $\frac{x_1}{t_1}$ and $\frac{x_2}{t_2}$, can you proceed from here?
