Question

How many milliliters of water must be added to 12 ml of a 60% salt solution in order to produce a 42% salt solution? Round your answer to the nearest tenth.


4.7 ml

5.1 ml

7.6 ml

7.2 ml

Answer 1

Let x = # of ml of water to add
0(x)+.6(12)=.42(x+12)

Answer 2

How many milliliters of water must be added to 12 ml of a 60% salt solution in order to produce a 42% salt solution? Round your answer to the nearest tenth.
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Equation:
salt + salt = salt
0*x + 0.60*12 = 0.42(x+12)
Multiply thru by 100 to get:
0 + 60*12 = 42x + 42*12
42x = 18*12
x = 5.1 ml (amt. of water needed)