Explanation:
9/4 Be +2 (the 9 and 4 are stacked next to Be). Atomic #: 4
Mass #: 9, # protons: 4, # neutrons: 5, #electrons: 2.
31/15 P (31 is stacked over 15 next to the P). Atomic #: 15,
Mass #: 31, # protons: 15, # neutrons: 16, # electrons: 15.
We can use a ratio to solve this question. Lets refer to the amount formed by the formula as a serving
1 serving needs 3/8 gal
We want to create 7/9 servings extra, so
1 + 7/9 = 16/7
1 : 3/8
16/7 : x
1/(3/8) = (16/7) / x
8 / 3 = 16x / 7
x = 7/6
He needs to use 7/6 gallons of water.
