To find the fewest number of jerseys for which Vendor B is cheaper than Vendor A, we can set up the total cost for each vendor as follows:
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Vendor A: Total cost = Delivery fee + Cost per jersey × Number of jerseys \[ C_A = 30 + 10x \] where \(x\) is the number of jerseys.
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Vendor B: Total cost = Delivery fee + Cost per jersey × Number of jerseys \[ C_B = 40 + 8x \]
We want to find the smallest integer \(x\) such that: \[ C_B < C_A \]
Substituting the equations, we get: \[ 40 + 8x < 30 + 10x \]
Now, let's simplify this inequality:
- Subtract \(8x\) from both sides: \[ 40 < 30 + 2x \]
- Subtract 30 from both sides: \[ 10 < 2x \]
- Divide by 2: \[ 5 < x \]
This means that \(x\) must be greater than 5. Therefore, the fewest number of jerseys needed for Vendor B to be cheaper than Vendor A is more than 5 jerseys.
Thus, the correct choice is:
More than 5 jerseys.