A scientist mixes water (containing no salt) with a solution that contains 35% salt. She wants to obtain 105 ounces of a mixture that is 30% salt. How many ounces of water and how many ounces of the 35% salt solution should she use?

90

Step-by-step explanation:

Start with changing 35% and 30% to a decimal.

35% =.35%

30% =.30%

Then multiply 105 by. 30%. (but don't put the percent sign in the calculator when multiplying)

105 x. 30% = 31.5

Then you want to divide 31.5 by. 35%

31.5 /.35% = 90