Question

how many grams of a 15% alchohol solution should be mixed with 40 grams of a 30% alchohol solution to obtain a solution that is 25% alchohol?

Answer 1

The number of grams is 20 grams

Let x represent how many grams of a 15 percent alcohol solution

First step

`15\%x+30\%.40/x+40=25\%`

Second step

`0.15x+0.4.30=0.25 \ (x+40)`

Simplify

`0.15x+12=0.25x+10`

`0.15x-0.25x=10+12`

`-0.1x=-2`

Divide both side by -0.1

`x=-2/-0.1`

`\bold{x=2}`

In conclusion, The number of grams is 20 grams