The ratio of the speed of boats ‘A’ and ‘B’ in still water is 8:9, respectively. The speed of the current is 25% of the speed of boat ‘A’ in still water. If boat ‘A’ takes 9 hours to travel 810 km downstream, then find the time taken by boat ‘B’ to travel 252 km upstream and 792 km downstream. (Note: Both the boats are rowing in the same stream.)
Let the speeds of boats ‘A’ and ‘B’ in still water be 8x km/hr and 9x km/hr Therefore, speed of the current = 0.25 × 8x = 2x km/hr According to the question, 8x + 2x = 810/9 Or, 10x = 90 Or, x = 9 Therefore, upstream speed of boat ‘B’ = 9x – 2x = 7x = 63 km/hr Downstream speed of boat ‘B’ = 9x + 2x = 11x = 99 km/hr Required time taken = (252/63) + (792/99) = 4 + 8 = 12 hours
A businessman's earning increase by 25%in one year but decreases by 4%in the next. Going by this pattern, after 5 years, his total earnings would be Rs....
A shopkeeper sells apples. He sells x% of the stock each day and x/5% of the remaining apples gets spoiled overnight, then he sells the remaining apples...
A chair is sold for Rs 720 after giving a discount of 10% on its marked price. The cost price of the chair is Rs 640. If it is sold at the marked price,...
If x is 80% of y, then what percent of 2x is y?
A spent 30% and 20% of his monthly salary on food and rent, respectively. Of the remaining amount, he gave 21% and 14% to his mother and brother, respec...
490 sweets were distributed equally among children in such a way that the number of sweets received by each child is 40% of the total number of children...
The respective ratio of monthly income of A to monthly income of B is 10:11, and A’s saving is (100/13)% more than B’s saving. Find the expenditure ...
Ganesh gives 30% of her salary to his wife, 12% of the remaining amount to his children and 10% of the remaining to his parents. If has given a total am...
Rajesh spent 40% and 20% of his monthly salary on food and rent, respectively. Of the remaining amount, he gave 15% and 30% to his mother and brother, r...
The marks scored by a boy in three subjects are in the ratio 2 : 3 : 4. Boy scored an overall aggregate of 75% in the exam. If the maximum marks in each...