A box contains nine bulbs out of which 4 are defective. If four bulbs are chosen at random, find the probability that all the four bulbs are defective.
Out of nine, five are good and four are defective. Required probability = ⁴C₄/⁹C₄ = 1/126
A box contains nine bulbs out of which 4 are defective. If four bulbs are chosen at random, find the probability that all the four bulbs are defective.
A box contains nine bulbs out of which 4 are defective. If four bulbs are chosen at random, find the probability that atleast one bulb is good |
Answer |
A bag contains 2 yellow, 3 green and 2 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue? |
Answer |
One year ago Jaya was four times as old as her daughter Nikitha. Six years hence, Mrs.Jayas age will exceed her daughters age by 9 years. The ratio of the present ages of Jaya and her daughter is : |
Answer |
Five years ago, the total of the ages of a father and his son was 40 years. The ratio of their present ages is 4 : 1. What is the present age of the father? |
Answer |
A father is twice as old as his son. 20 years ago the age of the father was 12 times the age of the son. The present age of the father is: |
Answer |
The total age of A and B is 12 years more than the total age of B and C. C is how many years younger than A ? |
Answer |
A persons present age is two-fifth of the age of his mother. After 8 years, he will be one-half of the age of his mother. How old is the mother at present |
Answer |
A father said his son , " I was as old as you are at present at the time of your birth. " If the father age is 38 now, the son age 5 years back was : |
Answer |
Sachin is younger than Rahul by 7 years. If the ratio of their ages is 7:9, find the age of Sachin |
Answer |
The ratio of the ages of father and son at present is 6:1. After 5 years the ratio of will become 7:2. The present age of the son is : |
Answer |