Answer: 1/4 cup of fizzy water
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Work Shown:
1/2 = 0.5
(1 cup fizzy water)/(2 tsp flavor) = (x cups fizzy water)/(0.5 tsp flavor)
1/2 = x/0.5
1*0.5 = 2*x ... cross multiply
0.5 = 2x
2x = 0.5
x = 0.5/2
x = 0.25
x = 1/4
He needs to add 1/4 cup of fizzy water
