Answer: j = 3d + 4
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Step-by-step explanation:
Referring to the answer above, the "+4" at the end represents the amount Desmond already has. He started off with 4 liters.
The 3d represents the 3 liters he gets per day, where d is the number of days.
So we combine the two elements getting 3d+4 representing the number of liters at any given day. That's why the answer is j = 3d+4
If we plug in d = 0, then j = 3d+4 = 3*0+4 = 4 liters is what he starts with.
If we plug in d = 1, then j = 3d+4 = 3*1+4 = 7 liters is what he has the following day. This shows Desmond gained 3 more liters.
If you plug in d = 2, you'll find that 3d+4 becomes 10, showing yet another 3 liters is added on. This process can go on for as long as you want.