Question
A boat can go 15 km upstream and 21 km downstream in 2
hours. If the speed of the stream is 3 km/h, then the time taken (in hours) by the boat to go 21 km upstream and 15 km downstream is:Solution
Let the speed of boat in still water =B
Let the speed of stream in still water =S
Speed of boat in downstream =B+S
Speed of boat in upstream =B-S
B+S=21/2=10.5km/h
B-S=15/2=7.5km/h
Solving after –
B=9km/h and S=1.5km/h
ATQ-
S =1.5 =3km/h
B=9=18 km/h
Now total taken time =
(21/B-S) +(15/B+S)
= (21/15) +(15/21)
=74/35
=2(4/35) hours
A paper is folded and cut as shown below. How will it appear when unfolded?
Pointing to a man on the stage Rashi said "He is the brother of the daughter of the wife of my husband". How is the man on the stage related to Rashi.
X # Y means 'X is the brother of Y'
X @ Y means 'X is the daughter of Y'
X & Y means 'X is the husband of Y'
X % Y means 'X is the ...
What should come in place of? in the given series based on the English alphabetical order?
ΤΟΥ, UQB, VSE, WUH, ?
Select the option in which the given figure is embedded (rotation is not allowed).
Given below is a statement followed by some conclusions. You have to take the given statement to be true even if it seems to be at variance with the co...
In a certain code language, 'FRY' is written as '147'. How will 'SEIZE' be written in that language?
Choose the one which is different from other three alternatives
Five girls P, Q, R, S and T sit around a circular table facing towards the centre (not necessarily in the same order). Only one girl sits between S and ...
Identify the figure from the given options that when put in place of the question mark (?) will logically complete the series.
