Question
The speed of a boat in still water is 20 km/hr. If the
boat covers 120 km in upstream in 12 hours, then find the time taken by the boat to travel 150 km in downstream.Solution
Let the speed of the boat in still water and the speed of the current be ‘x’ km/hr and ‘y’ km/hr, respectively Upstream speed of the boat = (x – y) = 120/12 = 10 km/hr Or, 20 – y = 10 Or, y = 20 – 10 = 10 km/hr Therefore, downstream speed of the boat = 20 + 10 = 30 km/hr Required time taken = 150/30 = 5 hours
A sum of Rs. 30,000 is invested in SIP 'C' which offers 12% p.a. simple interest for 3 years. The interest received from SIP 'C' is invested in SIP 'D' ...
Vaishali invested Rs. (X + 3000) on compound interest of r% p.a. compounded annually for 2 years and Tanushi invested Rs. (X – 2000) on simple interes...
If the difference between C.I. and S.I. is Rs. 512 at 20% rate of interest in 3 years, then find the principal on C.I.?
‘P’, ‘Q’ and ‘R’, each of them invested Rs. 2000 at the rate of 16% p.a., 24% p.a. and 36% p.a., respectively for 8 years, 3 years and 6 yea...
A sum doubles in 8 years at compound interest. In how many years will it become 4 times?
What will be the compound interest earned after 2 years on a deposit of Rs. 14,000 at an annual interest rate of 30%, compounded annually?
Rs. 5,000 is invested for 3 years in scheme ‘X’ offering simple interest at 8% per annum. The interest earned is equal to the interest obtained when...
- Sneha lends Rs. 10,400 on simple interest at 9% annually for 2 years. If she receives Rs. '2k' at the end, calculate the product of digits of 'k'.
Atul has Rs.350 with him. He invested 20% of the amount at 5% p.a. for 8 years and rest at 10% p.a. for 5 years. Find the sum of simple interests receiv...
On a principal of Rs. 2000, simple interest at R% per annum for 3 years is Rs. 480. Find the simple interest on Rs. 2500 at (R + 4)% per annum for 5 years.
Relevant for Exams:
