Answer:
Jenny needs £8 extra to buy the tiles.
Explanation:
Jenny's kitchen floor is in the form of trapezoid.
Area of a trapezoid =


= 28 meter²
One pack of tiles covers the area = 3 meter²
She needs the number of packs of tiles =


= 9.33
Therefore, she has to purchase 10 packs of tiles.
Since the price of one pack of tiles = £14.40
Price of 10 packs of tiles = 14.40 × 10
= £144
Price after using discount card of 25% = 144 -(25% of 144)
= 144 - (0.25 × 144)
= 144 - 36
= £108
Jenny has £100, so she needs £8 extra to buy the tiles.