Question
Speed of a boat in still water is 14 km/h while the
speed of stream is ____ km/h. Total time taken by the boat to go 140 km upstream and 210 km downstream is ____ hours. The values given in which of the following options will fill the blanks in the same order in which it is given to make the above statement true: I. 6, 26 II. 4, 22.5 III. 5, 25 IV. 7, 24Solution
For I: Speed of boat = 14 km/h Speed of stream = 6 km/h Speed in upstream = 14 – 6 = 8 km/h Speed in downstream = 14 + 6 = 20 km/h Total time = 140/8 + 210/20 = 17.5 + 10.5 = 28 hours So, I can’t be the answer. For II: Speed of boat = 14 km/h Speed of stream = 4 km/h Speed in upstream = 14 – 4 = 10 km/h Speed in downstream = 14 + 4 = 18 km/h Total time = 140/10 + 210/18 = 14 + 11.67 = 25.67 hours So, II can’t be the answer. For III: Speed of boat = 14 km/h Speed of stream = 5 km/h Speed in upstream = 14 – 5 = 9 km/h Speed in downstream = 14 + 5 = 19 km/h Total time = 140/9 + 210/19 = 15.56 + 11.05 = 26.61 hours So, III can’t be the answer. For IV: Speed of boat = 14 km/h Speed of stream = 7 km/h Speed in upstream = 14 – 7 = 7 km/h Speed in downstream = 14 + 7 = 21 km/h Total time = 140/7 + 210/21 = 20 + 10 = 30 hours So, IV can’t be the answer.
‘D’ and ‘E’ together can finish a task in 40 days, while ‘E’ and ‘F’ together can finish the same task in 30 days. ‘D’ and ‘E’ t...
- If a group of 15 boys and 10 girls can finish a task in 36 days, and a team of 5 girls alone can complete the same task in 72 days, how long will it take f...
A alone can complete 40% of a work in 18 days while B takes 15 days more than A to complete it. If B and C together can complete the work in 20 days, th...
‘M’ is 60% more efficient than ‘N’. ‘N’ started the work alone and worked for 20 days and after that ‘N’ is replaced by ‘M’. If the ...
- C is 37.5% more efficient than A, and A is 60% more efficient than B. If A, B, and C together can complete a task in 40 days, how long will it take A alone...
‘A’ and ‘B’ can do a piece of work in 12 days and 24 days, respectively. They started working together but ‘A’ left after 4 days. Find the t...
A, B and C alone can complete a work in 30, 60 and 45 days respectively. All of them started working together but after 3 days from start A left the job...
P, Q & R can finish a work in 10 days, 15 days, and 20 days, respectively, working alone. P and Q work on the first day, P and R work on the second day,...
Armaan and Bhanu working together can finish a certain task in 90 days, and Bhanu collaborating with Chintu can complete the same task in 70 days. If Ar...
Sneha and Meena can complete a project in 24 days and 60 days respectively. Sneha began working first. After how many days should Meena step in so that ...
