Answer:
$2784.51
Explanation:
You require ...
(total with tax) ≤ 3000
(total with tax) = (total before tax) + 0.0678·(total before tax)
So,
(total before tax) · 1.0678 ≤ 3000
total before tax ≤ 2809.51
With ...
total before tax = laptop cost + case cost
we have ...
laptop cost + case cost ≤ 2809.51
laptop cost ≤ 2809.51 - 25
laptop cost ≤ 2784.51
The maximum you can spend on a laptop is $2784.51.