Question
A boat goes 65 km in upstream in 5 hours and takes 4
hours to complete a distance of 20 km in downstream. Find the speed of boat in still water.Solution
Speed of boat in still water = (D + U)/2 Upstream speed (U) = 65/5 = 13 km/hr Downstream speed (D) = 20/4 = 5 km/hr Speed of boat in still water = (13 + 5)/2 = 18/2 = 9 km/hr
The average of 10 observations is 46. It was realized later that an observation was misread as 42 in place of 142. The correct average is:
Average age of company A is 22 years and average age of both companies A and B is 14 years. If the ratio of number of employees in company A and B is 3:...
In an examination, a student has an average score of 84. If he had scored 14 more marks in Science and 19 more marks in English, his average would incre...
In a class of ‘x’ students, if a new student weighing 32 kg joins the class, then the average weight of the class increases by 1 kg. If the ...
Average 20 numbers is ‘x’. If the average of first 12 numbers is 62.5 while average of last 5 numbers is 74.8 and 13th, 14th a...
Average age of company A is 24 years and average age of both companies A and B is 12 years. If the ratio of number of employees in company A and B is 3:...
- The average height of 30 boys is 165 cm and the average height of another group of 25 boys is 172 cm. What is the average height (in cm) of all the boys to...
In an election between two candidates, the winner secured a victory margin of 720 votes. If 20% of the total votes polled were de...
Average of 20 numbers is 90. Average of first 8 numbers is 103 while average of last nine numbers is 40. If ninth number is 25% less than the tenth numb...
Of the four numbers, whose average is 75, the first is one-fourth of the sum of the last three. The first number is
Relevant for Exams:
