Question
In still water, boat ‘X’ is three times as fast as boat
‘Y’. Boats ‘X’ and ‘Y’ are 240 km apart in a stream and are moving towards each other. They meet after 4 hours. What is the speed of boat ‘Y’ in still water, assuming they started at the same time?Solution
ATQ,
Let the still water speed of boat ‘Y’ = ‘y’ km/h
Then, still water speed of boat ‘X’ = 3 × y = ‘3y’ km/h
Let the speed of the stream = ‘x’ km/h
One boat is moving upstream and the other downstream,
So, effective relative speed = 3y + y = ‘4y’ km/h
Now, 4y = 240 ÷ 4 = 60
So, y = 60 ÷ 4 = 15
Speed of boat ‘Y’ in still water = 15 km/h
If an investment of Rs. 5,120 grows to Rs. 6,480 in two years when compounded annually at an interest rate of 'R%' per annum, calculate the value of 'R'.
A man invested Rs. 5,000 at simple interest of 'x%' p.a. and received Rs. 12,000 after 2 years. If he had invested Rs. 25,000 at simple interest of 'x%'...
A man deposited Rs. 12000 at 10% compound interest, compounded annually while Rs. 10500 at 13% simple interest per annum. What will be the difference be...
Rohit invested Rs. 3000 in scheme 'C' for 4 years and Rs. 4500 in scheme 'D' for 3 years. If the simple interest rate for both schemes is 15% per annum,...
Ravi lends Rs. 5,000 to two of his friends. He gives Rs.2500 to the first at 15% p.a. simple interest. Ravi wants to make a profit of 20% on the whole. ...
What is the maturity value of Rs.25000 at the end of 2 years at 9.25% Simple Interest?
- A sum of money amounts to Rs. 2040 at 18% per annum simple interest after 2 years. If the same sum is invested at the same rate of interest, but compounded...
A certain sum of money invested at 20% per annum for 2 years compounded annually, but if interest would have been compounded half yearly on the same amo...
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...
A man invests a sum of money in two schemes: Scheme A offers 12% simple interest per annum, and Scheme B offers 15% compound interest per annum. He inve...
Relevant for Exams:
