DI on Time speed distance boats streams new type

Answer the questions based on data given below. 1. On a particular day, the time taken by boat A to cover 255 km downstream is 2 hours more than the time taken by boat D to cover 195 km upstream. Find the ratio of upstream speed to downstream speed in case of boat A on that particular day. A) 4 : 11 B) 3 : 5 C) 15 : 22 D) 8 : 19 E) 7 : 17 2. Boat B covered 756 km downstream on Monday for which it took 6 hours less than that in which it covered half distance upstream on Tuesday. On Tuesday, speed of stream was 2 km/hr more than that on Monday. Find the downstream speed of boat B on Tuesday. A) 21 km/hr B) 19 km/hr C) 23 km/hr D) 11 km/hr E) 15 km/hr 3. For boat C, its upstream speed is 6 km/hr on a particular day. Find the difference in time in covering 360 km by boats A and C on that particular day. A) 8 hours B) 6 hours C) 4 hours D) 7 hours E) 5 hours 4. On a particular day, ratio of upstream speed to downstream speed of boat D is 3 : 7. It took 20 hours more to cover a distance upstream than same distance downstream by boat D. On that particular day, boat B covered same distance in how much time? A) 17.5 hours B) 15 hours C) 19 hours D) 19.5 hours E) 18.5 hours Upstream sped of boat E is 9 km/hr. How many more hours will it take to cover a distance of 315 km upstream than same distance downstream? A) 18 hours B) 20 hours C) 22 hours D) 25 hours E) 15 hours 1. Option A Solution: Let speed of stream on that day = x km/hr So (20-x)/(20+x) = 3/7 Solve, x = 8 km/hr So y/(20-8) – y/(20+8) = 20 Solve, y = 420 km So required time = 420/(16+8) = 420/24 = 17.5 hours 2. Option C Solution: Let on Monday, speed of stream is x km/hr, then on Tuesday it is (x+2) km/hr On Monday it covered 756 km, so on Tuesday it covered 756/2 = 378 km So 756/(16+x) = 378/(16-(x+2)) – 6 ………………(1) 126/(16+x) = 63/(14-x) – 1 OR SOlve with options in 378/[16 -(y+2 )] – 756/(16+y )=6 63 [1/(14-y) – 2/(16+y) ] = 1 Solve, x = 5 km/hr So speed of stream on Tuesday = (5+2) = 7 km/hr So downstream speed of boat B = (16+7) = 23 km/hr 3. Option B Solution: Upstream speed of C = 6 km/hr, so speed of stream: 9 – x = 6, x = 3 km/hr Downstream speed of boat C = 9+3 = 12 km/hr Downstream speed of boat A = 12+3 = 15 km/hr So difference in timings = 360/12 – 360/15 = 30 – 24 = 6 hours 4. Option A Solution: Let speed of stream on that day = x km/hr So (20-x)/(20+x) = 3/7 Solve, x = 8 km/hr So y/(20-8) – y/(20+8) = 20 Solve, y = 420 km So required time = 420/(16+8) = 420/24 = 17.5 hours 5. Option B Solution: Upstream speed = 9, speed of boat = 15 km/hr, so speed of stream = 15-9 = 6 km/hr Downstream speed = 15+6 = 21 km/hr So required time = 315/9 – 315/21 = 20 hours