Copier Z prints at a rate of 105 brochures in every 5 minutes and Copier A prints at a rate of 138 brochures in every 6 minutes. At 8 p.m., both copiers started printing. After a while, Copier Z stopped printing for some time as the ink cartridges were being changed before it continued to print again. Copier A continued printing during this time. At 10 p.m., the total number of brochures printed during the past two hours was 7807. Express the number of brochures printed by Copier Z as a percentage of the total number of brochures printed by both copiers. Round off your answer to 2 decimal places.
Number of brochures Copier Z prints per min = 105 ÷ 5 = 21
Number of brochures Copier A prints per min = 138 ÷ 6 = 23

From 8 p.m. to 10 p.m. = 2 h
1 h = 60 min
2 h = 120 min

Number of brochures printed by Copier A in 8 h
= 120 x 23
= 2760

Number of brochures printed by Copier Z in 8 h
= 7807 - 2760
= 5047

Percentage of the number of brochures that Copier Z printed over the total number of brochures printed
= ⁵⁰⁴⁷₇₈₀₇ x 100%
≈ 64.65%

Answer(s): 64.65%