Answer: 30 Oz of water should be added
Step-by-step explanation: Since 7% of the original solution is salt,
→ (.07)(70) = 4.9 Oz of salt.
Let the amount of water being added be W.
Then there will be
(70 + W) oz of solution, but still with 4.9 oz of salt.
Since we want the new solution to be 4.9% salt, we write:
.049 * (70 + W) = 4.9
→ 70 + W = 100 (by dividing both sides by .049),
→ W = 30 oz (by subtracting 70 from both sides), So the answer should be 30 Oz
