Question
A man can go on a motorboat with a speed of 18 km/hour
in still water to a certain upstream point and return to the starting point in a river that flows at a speed of 14 km/hour. Find the average speed of the motorboat for the total journey.Solution
Let the speed of the boat be b km/hour and the speed of the current be s km/hour. Average speed = 2xy/ (x+ y) (here, x is the speed of downstream and y is the speed of upstream)  = (2 (b +s) (b-s))/ ((b+ s +b -s)) = (b2 – s2)/b = (324 - 196)/18  = 128/18  = 64/9 Km/h
Quantity I: A number is first multiplied by 3 and then increased by 25%. The final result is 375. What is the original number?
Quantity II: A boa...
Quantity I:Â An article is marked 36% above its cost price and then sold at a disc...
I. 3x² + 17 x - 28 = 0
II. 3 y² -22 y + 24 = 0
Two quantities are given as Quantity I and Quantity II. You have to determine the relationship between them and give ...
In this problem, you're provided with two quantities, Quantity I and Quantity II, and your task is to solve both quantities and determine the correct r...
Quantity I: The ratio of expenditure of A, B and C is 16 : 12 : 9 and their total income is Rs. 1,530. Find the Share of B’s income if they save 20%,...
Quantity-I: The cost price of an article is Rs. 500. It is sold at a loss of 20%. Find the selling price.
Quantity-II: The cost price of an artic...
Which of the following pair of symbols will define the relation between Quantity I and Quantity II and between Quantity II and Quantity III respectively...
A mixture contains ‘X’ liter milk and ‘Y’ liter water. If 30 liter of mixture is taken out and replaced with water, then the quantity of milk an...
Quantity I: The cost price of a watch with a marked price of Rs. 500, which, after being sold at a 50% discount, still results in a profit of 25%.
...
Relevant for Exams:
