$4825.70
Explanation:
Cost for Fans: 4 x 675 = $2700
Cost for Lamps: 2 x 110 = $220
Cost for Switches: 5 x 41 = $205
Cost for Tubes: 6 x 135 = $810
Cost for Electric Wire: 230 x 2.50 = $575
Total cost: 2700 + 220 + 205 + 810 + 575 = $4510
Tax: Total cost x Tax rate = 4510 x 0.07 = $315.70
Total paid: Total cost + Tax = 4510 + 315.70 = $4825.70