Question
Total number of students in a class is 2160, and the
ratio of number of boys to girls is 2:3. If the number of boys and girls is increased by b% and (b – 6)% respectively, then the total number of students in the class will become 2430. Find the value of b.(Can calculate approx. value)Solution
ATQ, Number of boys in the class before increase = (2/5) ×2160=864 Number of girls in the class before increase = 2160 – 864 = 1296 According to the question: 
So, the value of b is approximately 16.1%.
A boat can row downstream at 24 km and upstream 16 km in 8 hours. Then what is the velocity of the current ?
A boat takes 7 hours to cover 259 km upstream and 9 hours to cover 477 km downstream. Find the time taken by the boat to cover 645 km upstream and 660 k...
Speed of a boat in still water is 4 times more than the speed of stream. If boat covers 108 km in downstream in 9 hours, then find the time taken by the...
Boat ‘A’ can cover 100 km in still water in 10 hours. In still water, if the ratio of the speed of boat ‘A’ to that of ‘B’ is 2:3 and the sp...
A boat travels 360 km downstream and 240 km upstream in 24 hours. If the ratio of the speed of the boat in still water to the speed of the stream is 5:1...
The speed of the stream is 14 km/h. Boat ‘A’ covers 64 km distance against the stream in 4 hours and boat ‘B’ covers 95 km distance against the ...
Two boats X and Y start towards each other from two places, 140 km apart. Speed of the boat X and Y in still water are 13km/hr and 15km/hr respectively....
When travelling with the current, a man takes 5 hours to cover the distance that he would've covered in 15 hours while travelling against the current. ...
A boat goes 24 km downstream in 3 hour and the same distance upstream in 6 hours. The speed of the boat in still water is:
The ratio of the speed of boat ‘A’ in still water, the speed of boat ‘B’ in still water and the speed of the current is 8:6:2, respectively. If ...
Relevant for Exams:
