Copier W prints at a rate of 115 letters in every 5 minutes and Copier X prints at a rate of 125 letters in every 5 minutes. At 5 p.m., both copiers started printing. After a while, Copier W stopped printing for some time as the ink cartridges were being changed before it continued to print again. Copier X continued printing during this time. At 7 p.m., the total number of letters printed during the past two hours was 7067. Express the number of letters printed by Copier W as a percentage of the total number of letters printed by both copiers. Round off your answer to 2 decimal places.
Number of letters Copier W prints per min = 115 ÷ 5 = 23
Number of letters Copier X prints per min = 125 ÷ 5 = 25

From 5 p.m. to 7 p.m. = 2 h
1 h = 60 min
2 h = 120 min

Number of letters printed by Copier X in 5 h
= 120 x 25
= 3000

Number of letters printed by Copier W in 5 h
= 7067 - 3000
= 4067

Percentage of the number of letters that Copier W printed over the total number of letters printed
= ⁴⁰⁶⁷₇₀₆₇ x 100%
≈ 57.55%

Answer(s): 57.55%