Exercise books

The school has a contract with a stationery store. When buying larger quantities of exercise books, it gets the following discount (the price is given per 1 piece).

Quantity	A4 exercise book M444 lined	A4 exercise book M440 blank	A5 exercise book 544 lined	A5 exercise book 540 blank
1 pc–100 pcs	0.44 eur	0.43 eur	0.22 eur	0.21 eur
101 pcs–500 pcs	0.42 eur	0.41 eur	0.21 eur	0.2 eur
501 pcs-1000 pcs	0.4 eur	0.39 eur	0.2 eur	0.19 eur
More than 1000 pcs	0.38 eur	0.37 eur	0.19 eur	0.18 eur

The deputy director ordered in June:

350 pcs of large lined exercise books number M444. One exercise book M444 cost eur. 350 pcs of these exercise books cost eur.
750 pcs of large blank exercise books M440. One exercise book M440 cost eur. 750 pcs of these exercise books cost eur.
1 500 pcs of small lined exercise books 544. One exercise book 544 cost eur. 1 500 pcs of these exercise books cost eur.
100 pcs of small blank exercise books 540. One exercise book 540 cost eur. 100 pcs of these exercise books cost eur.

a) How many euros in total did the school pay for the purchase of exercise books?
b) How many euros did Jakub save if he ordered via the school 2 large blank and 4 small lined exercise books and did not buy them himself at the stationery store?

Final Answer:

a =  745.5 Eur
b =  0.2 Eur

Step-by-step explanation:

$$\begin{gathered} a_1=350\cdot 0.42=147 \\ {a}_2=750\cdot 0.39=292.5 \\ {a}_3=1500\cdot 0.19=285 \\ {a}_4=100\cdot 0.21=21 \\ a=a_1+a_2+a_3+a_4=147+292.5+285+21=745.5\text{Eur} \end{gathered}$$

$b=2\cdot 0.43-2\cdot 0.39+4\cdot 0.22-4\cdot 0.19=0.2\text{Eur}$

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