Copier Y prints at a rate of 105 brochures in every 5 minutes and Copier Z prints at a rate of 136 brochures in every 4 minutes. At 2 p.m., both copiers started printing. After a while, Copier Y stopped printing for some time as the ink cartridges were being changed before it continued to print again. Copier Z continued printing during this time. At 4 p.m., the total number of brochures printed during the past two hours was 8148. Express the number of brochures printed by Copier Y 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 Y prints per min = 105 ÷ 5 = 21
Number of brochures Copier Z prints per min = 136 ÷ 4 = 34

From 2 p.m. to 4 p.m. = 2 h
1 h = 60 min
2 h = 120 min

Number of brochures printed by Copier Z in 2 h
= 120 x 34
= 4080

Number of brochures printed by Copier Y in 2 h
= 8148 - 4080
= 4068

Percentage of the number of brochures that Copier Y printed over the total number of brochures printed
= ⁴⁰⁶⁸₈₁₄₈ x 100%
≈ 49.93%

Answer(s): 49.93%