Question
The speed ratio of a stream to the upstream speed of a
boat is 1:9. A boat takes 2 hours and 30 minutes to travel 82.5 km downstream. Determine the time (in minutes) the boat will take to travel 54 km in still water.Solution
Let the speed of boat in still water and speed of stream be 'v' and 'x' km/h respectively. ATQ, x:(v - x) = 1:9 Or, 9x = v - x Or, 'v' = 10x -------- (I) Downstream speed = v + x = 10x + x = '11x' km/h So, 11x = (82.5/2.5) Or, 11x = 33 So, 'x' = 3 On putting value of 'x' in equation (I) , We get, 'v' = 10 X 3 = 30 Therefore, required time = (54/30) = 1.8 hours = 1.8 X 60 = 108 minutes
If A = (7)1/3 + (7) -1/3, then the value of {3A3 – 9A} will be:
If 1/(x+ 1/(y+ 1/z)) = 13/30, then find x+y+z= ?
If (5x - 2y) = 170 and 4x:3y = 32:9, then find the value of (3x² + y²).
If 2x + (1/9x) = 5, then find the value of 81x2Â + (1/4x2) - (1785/4)
If ( p = 60 - q - r ) and ( pq + r(q + p) = 1080), then find the value of ( p2 + q2 + r2).
If a = 7.250, b = 3.258 and c = 3.992 then value of a3-b3-c3-3abc is.
If (x – 3) is a factor of (x2 + 4qx – 2q), then the value of q is:
- Find the value of (21)³ + (- 12) ³ + ( - 9)³.
A solid metallic sphere of radius 15 cm is melted and recast into spherical balls of radius 3 cm each. What is the ratio of the surface area of the orig...
Relevant for Exams:
