Given: Pages printed by A and B = 2400 Hours of work = 5 Days of work = 5 A’s 2.5 hrs work = B’s 1.5 hrs work Concept: Calculate the work done by A and B in 1 hour and then equate the work done by them with the total work done in 5 days. Formula used: Total unit of work = Work done by (A + B) in 1 hour × No of hours of work in 1 day × No of days of work Calculation: ∵ A’s 2.5 hrs work = B’s 1.5 hrs work ⇒ A × 2.5 = B × 1.5 ⇒ A/B = 1.5/2.5 ⇒ A/B = 3/5 Let, A’s one hour’s work = 3x B’s one hours work = 5x ∴ (5x + 3x) × 5hr × 5 days = 2400 pages ⇒ 8x × 5 × 5 = 2400 ⇒ x = 2400/(8 × 5 × 5) ⇒ x = 12 ∴ Pages printed by B in 1 hour = 5x = 5 × 12 = 60 pages.