Exams › SSC CGL (Prelims) › Maths

The speed of a boat in still water is 18 km/h and the speed of the stream is 3 km/h. How much time, in hours, will it take to cover a distance of 105 km downstream and then return upstream?

1. 12
2. 10
3. 15
4. 9 2/7

Correct answer: 12

Solution

Downstream speed = 18 + 3 = 21 km/h and upstream speed = 18 - 3 = 15 km/h. Time taken = $105/21 + 105/15 = 5 + 7 = 12$ hours.

Related SSC CGL (Prelims) Maths questions

• A boat covers a distance of 55 km downstream in 5 hours, while it takes 11 hours to cover the same distance upstream. What is the speed of the boat in still water?
• A boat can go 54 km upstream in 6 hours. If the speed of the stream is 4.8 km/h, then how much time will the boat take to cover a distance of 279 km downstream?
• The speed of a boat in still water is 12 km/h. If it can travel 30 km downstream in 2 hours, what is the speed of the stream?
• A number whose fifth part increased by 5 is equal to its third part decreased by 7. Find half of the number.
• If (48^ + k) is an acute angle and sin(48^ + k) = cos 13^, what is the value of k (in degrees)?
• If ₹1,875 becomes ₹2,625 in 4 years, what will ₹24,000 become at the end of 9 years at the same rate of interest, under simple interest?

⚔️ Practice SSC CGL (Prelims) Maths free + battle 1v1 →