Question
A boat's speed while moving downstream is 60% higher
than its speed while moving upstream. If the boat covers 720 km downstream in 18 hours, determine its speed in still water.Solution
ATQ; Let the speed of the boat in still water and the speed of the stream be ‘x’ km/h and ‘y’ km/h, respectively. Downstream speed of the boat = (x + y) km/h Upstream speed of the boat = (x – y) km/h Downstream speed of the boat = (720/18) = 40 km/h
According to the given condition, (x + y) = 40 ------- (I) And, 40 = 1.6 × (x – y) Or, (x – y) = 40 / 1.6 = 25 -------- (II) By adding equation (I) and equation (II), we get x = 32.5 km/h Therefore, the speed of the boat in still water = 32.5 km/h
In a general survey of 832 people, it was found that 624 owned a car. If a person is selected randomly, what is the probability that the person will not...
If the homogeneous system of equations
x + y + z = 0
2x + 3y + 4z = 0
has a non-trivial solution, then the value of k is:
3x + 5y + kz = 0
Quantity I: Tara invested a certain amount in a simple interest scheme at a rate of 18% per annum for 5 years, while Rina invested the same amount in a...
The height of a right circular cone is 7 cm, and its volume is 733(1/3) cm³. Determine the diameter of the cone.
A person sells two items, X and Y. The marked prices of X and Y are 25% and 40% higher than their cost prices, respectively. After a 10% discount on bot...
The value of integration of log x / x2 is:
A man invests ₹20,000 in a scheme that offers a 10% simple interest per annum. After how many years will his total amount become ₹30,000?
A container has 80 liters of pure milk. 20 liters of milk is removed and replaced with 20 liters of water. Then, 20 liters of the new mixture is removed...
A boat takes 8 hours to travel 42 km upstream and 81 km downstream combined. In another instance, it covers 48 km upstream and 54 km downstream in 7 hou...
Relevant for Exams:
