subash can copy 50 pages in 10 hrs . subash and prakash together can copy 300 pages in 40 hours . in how much time prakash can copy 20 pages .
"subhas ' s 1 hr copy page = 50 / 10 = 5 page ( subhas + prakash ) ' s 1 hr copy page = 300 / 40 = 7.5 page from above prakash ' s 1 hr copy page = 2.5 page so time taken in 20 page ' s copy = ( 20 / 2.5 ) = 8 hrs answer : a"
floor(subtract(divide(300, 40), divide(50, 10)))