相中2條中一數學題目求解答！！！！?

12.
(a)
Total amount received
= [$800 × 60% (1 + 40%)] + [$800 × (1 ‒ 60%) × (1 ‒ 50%)]
= $832

(b)
Total amount received = $832 > Cost
Hence, profit is made.

Overall profit percentage
= [(832 ‒ 800)/800] × 100%
= (32/800) × 100%
= 4%


13.
(a)
Total amount received
= $(8/15) × 200 × (1 ‒ 10%)
= $96

(b)
The loss percentage
= [(120 ‒ 96)/120] × 100%
= (24/120) × 200%
= 20%