A can write 100 pages in 25 hours. A and B together can write 210 pages in 30 hours. In what time can B write 42 pages?

Question: A can write 100 pages in 25 hours. A and B together can write 210 pages in 30 hours. In what time can B write 42 pages?Solution:Given,In 25 hours A can write 100 pages∴ In 1 hour A can write 100/25 pages= 4 pagesHere,∴ In 1 hour A and B together can write 210/30 pages= 7 pagesand,B's 1 hour work = (A + B)'s 1 hour work - A's 1 hour work= 7 - 4= 3 pages/hourB's time3 pages in 1 hour∴ 1 page in 1/3 hour∴ 42 pages in = (1 × 42)/3 hour= 14 hours