A scientist mixes water (containing no salt) with a solution that contains 45% salt. she wants to obtain 180 ounces of a mixture that is 30% salt. how many ounces of water and how many ounces of the 45% salt solution should she use?

Solution contains 45% salt

She wants to obtain 180 ounces of a mixture that is 30% salt

Ounces of water with 45% salt solution = ?

30% = 0.3 and 45% = 0.45

Let V is the volume of water to be mixed in ounces, then the volume of the 45% salt solution needed is 180-V

The balanced equation for the mass of salt is

0.45 x (180-V) = 0.3 x 180

81 - 0.45V = 54

0.45V = 81-54

0.45V = 27

V = 60

So, 60 ounces of water is needed