Question
The combined speeds of boats 'P' and 'Q' in still water
amount to 52 km/hr. The current's speed affecting boat 'P' is 25% greater than that affecting boat 'Q'. Boat 'Q' can cover 1927 km downstream in 41 hours, while boat 'P' takes 47 hours to cover the same distance downstream. Determine the upstream speed of boat 'P'.Solution
ATQ, Speed of boat ‘P in still water be ‘p’ km/hr Therefore, speed of boat ‘Q’ in still water = (52 – p) km/hr Let the speed of the current for boat ‘Q’ be q km/hr Therefore, speed of current for boat ‘P’ = 1.25q km/hr According to the question, (p + 1.25q) = 1927/47 = 41 ….. (1) Also, (52 – p + q) = 1927/41 = 47 …. (2) On solving equation (1) and (2), we get Speed of boat ‘P’ in still water = p = 21 km/hr Speed of the current for boat ‘Q’ = q = 16 km/hr Therefore, speed of the current for boat ‘P’ = 1.25q = 20 km/hr Therefore upstream speed of boat ‘P’ = p – 1.25q = 21 – 20 = 1 km/hr
A certain sum of money invested at R% p.a. fetches a compound interest (compounded annually) of 1525.5 and simple interest of Rs.1500 at the end of 2 ye...
Naina lent Rs. 9,800 to Mohini for 4 years and Rs. 8,800 to Mitali for 6 years on simple interest at the same rate of interest and received Rs. 11,040 i...
A person invested a sum of Rs. 9000 at r% per annum at simple interest and a sum of Rs. 13500 at (r-4)% at simple interest. If total interest earned on ...
A sum of money doubles itself in 5 years in how many years it will be 3 times?
What will be the ratio of simple interest earned by certain amount at the same rate of interest for 4 years and 6 years ?
Find the total amount returned by Manish to the bank at the end of three years, when Rs.24000 is borrowed at the rate of (25/2)% compounded annually?(ca...
Simica invested a certain amount of money at a simple interest rate of 12.5% per annum and earned Rs. 2,400 as interest over 3 years. If Tabu invested t...
A sum of money lent at 5% rate of simple interest. The difference between interest for 6 years and 4 years is Rs. 2000. Find the principal amount.
An initial principal sum of Rs. 8000, invested by Pranav, accrued interest at a compound rate of 20% annually for a period of 2 years. Subsequently, the...
If Rs. 15000 is invested at 14% per annum, compounded yearly, calculate the interest earned in one year.
Relevant for Exams:
