For each order, a mail-order bookseller charges a fixed processing fee and an additional shipping fee for each book in the order. Rajeev placed five different orders with this bookseller--an order for 1 book in January, an order for 2 books in February, an order for 3 books in March, an order for 4 books in April, and an order for 5 books in May. What was the total of Rajeev's processing and shipping fees for these five orders?
(1) Rajeev's processing and shipping fees were $1.00 more for his order in March than for his order in January.
(2) The total of Rajeev's shipping fees for the five orders was $7.50.
ANS:E
我想請問一下為甚麼不是C呢?
(1)P+3S=(P+S)+1
(2)P+5S=7.5
2個未知數2個方程式~不就可以解出P跟S了嗎??
謝謝大家~~
