Maths by Mr. M. P. Keshari
Example 4. Out of 400 bulbs in a box, 15 bulbs a defective. One ball is taken out at random from the box. Find the probability that the drawn bulb is not defective.
Solution:- Total number of bulbs = 400
Total number of defective bulb = 15
Total number of non-defective bulbs = 400-15
= 385
P (not defective bulb) = 385/400
= 77/80
Example 5. Find the probability of getting 53 Fridays in a leap year.
Solution:- No. of days in a leap year = 366
366 days = 52 weeks and 2 days.
A leap year must has 52 Fridays
The remaining two days can be
Out of 7 case, 2 cases have Friday
P (53 Friday) = 2/7
| Subjects | Maths (Part-1) by Mr. M. P. Keshari |
| Chapter 9 | Circle |
| Chapter 10 | Tangents to a circle |
| Chapter 11 | Geometrical Construction |
| Chapter 12 | Troigonometry |
| Chapter 13 | Height and Distance |
| Chapter 14 | Mensuration |
| Chapter 15 | Statistics |
| Chapter 16 | Probability |
| Chapter 17 | Co-ordinate Geometry |