Track quiz
Twelve quick questions, one for each lesson. Use the table if you get stuck.
| Idea | Remember |
|---|---|
| The rule | P(E) = favourable ÷ total, when all outcomes are equally likely. |
| Two spinners | Write each result as a pair, in order. One cell each. |
| Two dice | 36 pairs. The 11 sums are not equally likely. |
| 0 to 1 | Impossible = 0. Sure = 1. Never below 0 or above 1. |
| Equal chance | Count slips, not the numbers on them. |
| Not | P(not E) = 1 − P(E). |
| Or | Count each outcome once. Check for shared ones first. |
| All together | Count all, check equal, count wanted, use the rule, check. |
| Coins | List every result in order. HT and TH are different. |
| Pack of 52 | Count the cards that fit, out of 52. |
| Number words | Read each number word. Then list the numbers. |
| Kept out | A marble kept out lowers the total by 1. It lowers its own colour by 1. |
A jar has slips 3, 5, 5, 5, 8, 8. You pick one. A student says P(5) = 1/3, "because there are 3 numbers". What is right?
Spinner A has parts 1 to 5. Spinner B has parts 1 to 4. How many cells, and what is P(same number)?
Two dice are thrown. What is P(sum 9)?
A die shows 1 to 6. A student writes P(7) = −1/5. What is right?
Slips 1 to 8. What is P(more than 2), the quick way?
Slips 1 to 10. A student says P(odd or a multiple of 4) = 7/10. Is that right?
12 cards: 3 colours, each with the numbers 1 to 4. You pick one. What is P(not a 1)?
A jar has slips 2, 4, 6, 8, 10, 12. You pick one. What is P(a multiple of 4)?
Three coins are tossed together. A student counts four head-groups. She says P(at least one tail) = 3/4. What is right?
One card is drawn from a pack of 52. What is P(a red card or a queen)?
Tickets are numbered 1 to 20. One is drawn. What is P(a number between 5 and 12)?
A bag has 3 red and 9 green marbles. A green marble is kept out. What is P(the next marble is green)?
Now open Chapter 14, Probability, in your NCERT Maths book. Try its exercises. You are ready.