A can copy 50 papers in 10 hours while both A & B can copy 70 papers in 10 hours. Then for how many hours required for B to copy 26 papers?
2007-02-01 05:16:50 · 3 answers · asked by santosh 1 in Science & Mathematics ➔ Mathematics
B can copy 20 papers in 10 hours.
=> B can copy two papers/hour
=> B can copy 26 papers in 13 hrs
edit: typo
2007-02-01 05:27:32 · answer #1 · answered by Kirstin 2 · 0⤊ 0⤋
13 hours.
A & B together do 70 in 10 hours and A does 50 of them in the 10 hours, so 70 - 50 = 20 papers that B did in the 10 hours. So, a simple proportion finishes this one:
20 papers : 10 hours :: 26 papers : X hours or 20 papers / 10 hours = 26 papers / X hours so 20/10 = 26/X and 2X = 26 so 2X/2 = 26/2 and finally X = 13 hours.
2007-02-01 13:29:48 · answer #2 · answered by roynburton 5 · 0⤊ 0⤋
A=50 papers/10 hours = 5 papers/hour
A+B=70 papers/10 hours = 7 papers/hour
B=7- A
B= 7-5 = 2 papers/hour
26 papers @ 2 papers/hour = 13 hours
2007-02-01 13:28:49 · answer #3 · answered by mamacath 2 · 0⤊ 0⤋