The table shows the charges for printing at a printing company. The cost per piece is based on the total number of copies to be printed. 

1. Roshel wanted to place an order to print 320 A3-size copies of her poster. How much did she need to pay?
2. Eric placed an order to print some A4-size copies of his poster. John placed an order to print some A3-size copies of his poster. Both of them ordered an equal number of copies of their posters. The total cost of their orders was $137.10. How many A4-size copies of the poster did Eric print?

(a)
Amount that Roshel needed to pay
= 40 + 320 x 0.50
= $200

(b)
Total cost = $137.10

Printing cost excluding the basic printing charges
= 137.10 - 30 - 40
= $67.10

Amount of 1 A4 copy and 1 A3 copy if the cost per piece was between 1 to 49
= 0.60 + 1.00
= $1.60

Number of sets if the number of copies that each boy printed was between 1 to 49
= 67.10 ÷ 1.6
≈ 41.9 (x) (Number of sets must be a whole number and is between 1 to 49.)

Amount of 1 A4 copy and 1 A3 copy if the cost per piece was between 50 to 99
= 0.35 + 0.75
= $1.10

Number of sets if the number of copies that each boy printed was between 50 to 99
= 67.10 ÷ 1.1
= 61 (✓) (Number of sets must be a whole number and is between 50 to 99.)

Number of A4-size copies of the poster that Eric printed = 61

Answer(s): (a) $200; (b) 61