Question
Among a set of 4 black balls and 3 white balls, how
many selections of 3 balls can be made such that at least 2 of them are black balls?Solution
Selecting at least 2 black balls from a set of 4 black balls in total selection of 3 balls can be 2 black and 1 white balls 3 black and 0 white balls Therefore, our solution expression looks 4C2 × 3C1 + 4C3 × 3C0 6 X 3 + 4 X 1 = 18 + 4 = 22 ways
A sum of ₹15,625 is invested for 2 years at an annual interest rate of 8%. For the first 1.5 years, the interest is compounded semi-annually, and for ...
Mr. X invested Rs. 500 in two schemes, A and B in the ratio of 7:3, respectively. Scheme A and B are offering simple interest at rate of 12% per annum a...
- Neha deposits Rs. 9,000 at a simple interest rate of 7% per annum for 5 years. What amount will she get at the end of the term?
A man invested a certain amount of sum at 10% per annum simple interest and earned an interest of Rs. 3000 after 5 years. If the same amount is i...
Sunil invested Rs. ‘4x’ in scheme ‘A’ offering simple interest of 25% p.a. and reinvested the interest earned from scheme ‘A’ at the end of ...
Dinesh invested Rs. (P-500) at the rate of 27% per annum on simple interest and at the end of three years, he got Rs. 4860 as an interest. Pankaj invest...
Anjali invested Rs.15000 in a scheme offering compound interest of x% p.a. compounded annually. If at the end of 2 years, interest received by her from ...
The profit earned when article is sold for Rs. 1280 is 23 times of the loss incurred when it is sold for Rs. 800.Find the CP?
- Ravi invested Rs. 2500 at (R + 4)% p.a. simple interest and earned an interest of Rs. 1500 at the end of 3 years. Find the interest earned if the same amou...
- A certain sum doubles in 9 years at certain rate of simple interest. The same sum under the same interest rate will become 4 times of itself in how many ye...
Relevant for Exams:
