Question
A car covers a distance of 450 km at a constant speed.
If the car’s speed had been 15 km/h faster, it would have taken 1 hour less to cover the same distance. What is the original speed of the car?Solution
Let the original speed of the car be x km/h. Time taken = 450/x. With the new speed (x + 15), time taken = 450/(x + 15). According to the question: 450/x − 450/(x + 15) = 1. Solving this: 450(x + 15 − x) = x(x + 15). 450 × 15 = x² + 15x. x² + 15x − 6750 = 0. Solving for x, we get x = 75 km/h. Thus, the original speed is 75 km/h Ans. d
A person invested some amount at the rate of 12% simple interest and a certain amount at the rate of 10% simple interest. He received yearly interest of...
The compound interest on a certain amount for 2 years at 4% per annum is ₹ 1,020, if interest is compounded annually. Find the simple interest on that...
Rs. x is invested at simple interest at the rate of 10% per annum for 3 years. If Rs. (x + 300) is invested at the same rate of interest for the same p...
If a certain sum becomes 5 times of itself in 2 years when invested at certain rate (per annum) of simple interest, then find the rate of interest.
A woman invested Rs. 'x + 500' at 8% per annum simple interest and received Rs.360 as interest after 3 years. Calculate the interest she would earn if s...
A sum of money invested for 2 years at 20% compounded annually and similar money invested for 3 years on simple interest at 10% per annum. If the differ...
Soham invested Rs. 32,000 partly in schemes ‘I’ and ‘J’ for 4 years and 6 years, respectively. Scheme ‘I’ offers simple interest at 18% per ...
The simple interest on a sum of Rs 5000 at 8% per annum for 3 years is:
A sum of Rs. 3200 is invested at simple interest for 2 years. If the rate interest for first year is 12% p.a. while 20% p.a. for second year, then find ...
In how many years will a sum of ₹10,000 become ₹13,310 at 10% compound interest per annum, compounded annually?
