<h2>
Answer:</h2>
17
<h2>
Step-by-step explanation:</h2>
Cost per Packet * Number of Packets + Shipping = Amount to Spend
0.90 * b + 2.50 = A
You can spend a maximum of $18.50
A < 18.50
Rearrange the formula to find b
Number of Packets = Amount to Spend - Shipping / Cost per Packet
18.50 - 2.50 = 16.00 / 0.9 = 17.7...
You can't have 0.7 of a packet so you have to round down to 17.
Now if you put it into the original formula:
0.90 * 17 + 2.50 = 17.80
And 17.80 is less than 18.50.
