Answer:
20 packets of biscuits
Step-by-step explanation:
The expense formula is
E = 200 + 5n
The income formula is
I = 15n
The break-even point occurs when income = expenses:
I = E
15n = 200 + 5n
Subtract 5n from both sides:
15n - 5n = 200
10n = 200
n = 200/10
= 20 packets of biscuits