Capgemini
Company
Numerical Ability
Boats and Streams
A boat starts from point A and goes to point C which is 200 m away. B is 80 m away from A on the way to C. All these three points are on the same bank of the river which flows at 2 m/s. The boat man moves in the direction of the river on the way from A to C and on the way back paddles against the river along the same route. The speed of the boat in still water on the way from A and B (or from B to A) is half of the same from B to C (or from C to B). The boat takes 2 min 21 s to start from A and return to its original position. If the boatman started back immediately on arrival at C, the speed of the boat in still water from A to B could be
Read Solution (Total 4)
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- Distance between A to C = 200m
distance between A to B = 80m
hence distance between B to C = 120m(A, B and C are on same bank)
Let the speed of boat in still water between A and B is 'x'm/s
=>speed of boat in still water between B and C is '2x'm/s
Actual speed of boat(upstream) between A to B: 'x+2'm/s & between B and C: '2x+2'm/s
downstream velocities( from C to A): C to B: '2x-2'm/s & B to A: 'x-2'm/s
total time taken for round trip=2 min 21s=141s
using time= distance/velocity
=>80/(x+2)+120/(2x+2)+120/(2x-2)+80/(x-2)=141 (i.e., A->B->C->B->A = 141s)
Its becomes a very complex equation(polynomial of degree 4 with large coefficients) to solve manually. It will be easy if options are given. The option which satisfies the above equation for 'x' will be the answer!
- 11 years agoHelpfull: Yes(6) No(1)
- option
a-2
b-2.5
c-3
d-4
so 3 satisfy the above equation - 11 years agoHelpfull: Yes(3) No(0)
- Can any 1 help me in this problem
- 11 years agoHelpfull: Yes(1) No(0)
- 80/(x+2)+120/(2x+2)+120/(2x-2)+80/(x-2)=141 (i.e., A->B->C->B->A = 141s)
substitute value of x as 3 i.e x=3.
then the time will be
141 seconds. ie same as 2min 21 sec.. so the ans is 3m/sec - 9 years agoHelpfull: Yes(0) No(0)
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