Question
The speed of the boat in still water is 12 km/hr and the
speed of the stream is 9 km/hr. A boat goes 84 km downstream with its usual speed but at the time of returning the speed of the boat in still water is doubled. Find the total time taken by boat to cover the whole distance.Solution
According to the question, Required time = 84/(12 + 9) + 84/(24 – 9) => 84/21 + 84/15 => 4 + 5.6 = 9.6 hours
- Ravi invested ₹P in a compound interest scheme at an annual interest rate of r% for 1 year. Meanwhile, Kriti invested ₹2P in a simple interest scheme a...
- If he invested Rs. ________ in a scheme that offers a R% rate of interest for the 4T years on simple interest, then the interest received from the schem... 
- Aman spends 30% of his income, monthly income, on fuel. 40% in basic needs and 20% of the remaining in education. He saves the rest of them all in a rec... 
- A took a loan of Rs.4880 at simple interest of 25% p.a. and invested the same money in a scheme at simple interest of 35% p.a. Find the profit earned by... 
- A man invested Rs.22000 in a fixed deposit scheme for 3 yrs at CI of 5% p.a. How much will a man get on maturity of the fixed deposit? 
- Raghav has made financial investments in two different Gold Schemes. In Gold Scheme P, he invested a certain amount denoted by 'a' for 2 years with an a... 
- A man invested certain sum at simple interest of r% p.a. such that it amounts to 110% of itself in 4 years. Find the interest earned when Rs. 3400 is in... 
- An amount of Rs. 2,500 invested at a simple interest rate of r% per annum grows to Rs. 4,930 in 6 years. Using the same rate of interest, in how many ye... 
- A sum of money will amount to Rs. 250 in 2 year & in 3 year it is to be 350 in compound interest . Find the rate of interest? 
- A person invests ₹8000 in a scheme offering 5% simple interest per annum. After 2 years, the total amount becomes ₹8800. How much interest is earned...