Question
The speed of the boat in still water is 20% less than
the speed of the boat in downstream. The time taken by the boat to cover 780 km distance in upstream is (t+3) hours. If the speed of the stream is 20 km/h, then find out the value of ‘t’.Solution
ATQ, Let ‘B’ be the speed of the boat in still water and ‘S’ the speed of the stream, with S = 20 km/h. B = (100-20)% of (B+S) = 80% of (B+S) = 0.8(B+S). B = 0.8(B+20), which leads to B = 0.8B + 16, thus 0.2B = 16, giving us B = 80 km/h. With the boat covering 780 km upstream, where upstream speed = B - S = 80 - 20 = 60 km/h, we have 780/(t+3) = 60. Solving for t yields t+3 = 780/60 = 13, Hence, t = 10. Value of ‘t’ = 10.
In a village election between two candidates, the winner secured 70% of the total votes cast and won by a majority of 13000 votes. How many votes did th...
75% of A is equal to 40% of C and 80% of B is equal to 100% of A. If sum of 50% of B and 30% of C is equal to 95, then find 80% of A.
The income of 'Amit' surpasses that of 'Bhishma' by a certain percentage. If the average of their incomes amounts to Rs. ____, then the individual incom...
A towel was 75 cm long and 120cm broad. When bleached, it was to have lost 40% of its length and 20% breadth. The percentage of decrease in area is:
A and B have monthly incomes in the ratio of 6:5, respectively. Both save the same amount each month. A's monthly expenses are five times B's monthly sa...
A man donated 25%, 13% and 27% of his income to three NGOs ‘A’, ‘B’ and ‘C’, respectively. They spent 75%, 80% and 50% of respective sums re...
Monthly income of P is Rs.20000 and his monthly savings is Rs.12000. If his monthly income is decreased by 40% and monthly expenditure is decreased by 3...
In a given years, A sold 2000 caps while B sold 55% more number of caps than A and C sold 20% less number of caps than B. Find the ratio between the num...
Raj saves Rs. 7500 more if he spends 60% of his income instead of 90%. Find the savings of Sanjay whose income is 30% more than that of Raj, and spends ...
The total strength of school A is 20% more than that of school B. In school A and B, out of total number of students, 20% and 50% respectively are girls...
