Question
A boat can travel 225 km
downstream in 5 hours. If the speed of the boat in still water is 7 times the speed of the stream, how much time will it take for the boat to cover 84 km upstream?Solution
ATQ, Let the speed of the stream be 'x' km/hr Therefore, speed of the boat in still water = 'x' + 7x = '8x' km/hr According to the question, Downstream speed of the boat = 8x + x = (225/5) = 45 Or, 9x = 45 Or, x = (45/9) = 5 Therefore, upstream speed of the boat = 8x - x = 7x = 7 X 5 = 35 km/hr Therefore, required time taken = (84/35) = 2.4 hours
Find the radius of the sphere whose volume is 562.5π cm3
What will be inradius of a right angle triangle whose base is 11 cm & height is 60 cm ?

The lengths of three medians in a triangles are 15 cm, 20 cm, 25 cm. What is the area of that traingle (in cm 2 )?
If the volume of a cube is 64cm³, then the diagonal of cube is
In a triangle ABC, AB = 13 cm, BC = 14 cm, and AC = 15 cm. Find the area of the triangle and the length of the altitude from vertex A to side BC.
If I is the incentre of ΔABC , if ∠ BAC = 450 , then what is the measure of ∠ BIC?
In the figure given below, AC = 16 cm and BF = 5 cm. If AE:CE = 5:3, then find the perimeter of ΔABC.
If I is the incentre of ΔABC , if ∠ BAC = 700 , then what is the measure of ∠ BIC?
In a circle, the chord AB is 12 cm, and the perpendicular from the center O to the chord AB bisects it at point P. If OP = 5 cm, what is the radius of t...