I have trouble with solving the following mixtures problem.

> 
> A tank of 380 liters is full of brine with a concentration of 113 grams of salt per liter. How much salt per minute needs to be added per minute so that, when 19 liters remain, the concentration is 227 grams of salt per liter, if brine drains at a rate of 3.8 liters per minute?
> 
> 
> 

The differential equation should be:

```
y'[t] == p - 3.8*y[t]/(380 - 3.8 t), 

```

where `p` is the rate at which salt is added, the unknown I am searching for.

When I imput it into the program it fails to solve it.

```
DSolve[y'[t] == p - 3.8/(380 - 3.8 t)*y[t], y[t], t].

```

However, if I replace `p` a number beween -2.7 to 2.7 it works. It also does if I put 2 E or any other number multiplied by Euler's number. I tried solving it using `p = p*e`, which did work, however I get laughably small numbers (10^-15) for `p`.

The printed answer is `114/Log[20]`, aproximately 38.05g/min.

Am I inputting something wrong?