Answer:
436 items
Step-by-step explanation:
When a quantity A is inversely proportional to another quantity B, we can write:

Where k is the proportionality constant [that we need to find]
For this problem, we can write the ratio as:

Now given N = 480 and C = 4.90, we first find k:

Now, as second step, we need this time to find N, when
C = 5.40
Note, we know know k = 2352, so we find N:

Rounding to next whole number, we have 436 items