Question
Motor boat covers a certain distance downstream in a
river in 20 hours. It covers the same distance upstream in 30 hours. If the speed of the water is 12 km/hr, then the speed of the boat in still water is:Solution
Let the distance be ‘D’ km According to the question, Downstream speed x + y = d/20 or d = 20 (x+y) .......... (i) Upstream speed x-y = d/30 or d = 30(x-y) ........... (ii) Comparing (i) & (ii) 20(x+y) = 30(x-y) 2(x+y) = 3(x-y) 2x + 2y = 3x - 3y x = 5y Hence, y = Speed of the current = 12 km/hour. Speed of boat, x = 5 × 12 = 60 km/hr
The ratio of length to breadth of a rectangle is 5:4, respectively. Perimeter of rectangle is 234 cm. If each side of a square is 25% more than the brea...
The difference between the length and breadth of a rectangle is 23 m. If its perimeter is 174 m, then its area is
Axar purchased several cubical boxes at Rs. 12 each and placed them into a cuboidal box that perfectly fits these cubes. The curved surface area of the ...
Find the number of silver balls of diameter 2 cm each, that can be made from a sphere of diameter 32 cm?
The perimeter of a rectangle is 230 meters, and the difference between length and breadth is 15 meters. Find the area of the rectangle.
The radius of a circle is equal to the radius of base of a cone. If the diameter of the circle is 35 cm and the height of cone is 18 cm, then find the v...
The length of a width is 21 cm and the side of a square is 25 cm less than the length and width of the rectangle. If perimeter of the rectangle is 30 cm...
The length of a rectangle is 5 metres more than its width. If the perimeter of the rectangle is 62 metres then what is the area (in m2Â ) of ...
The side of a square is equal to the perimeter of an equilateral triangle of area 25√3 cm2 . Find the area of the square?Â
On a rectangular wall of length 35 metres and height 30 metres, there is a window in the shape of triangle surmounted on a square. If the base of triang...
Relevant for Exams:
