A student

A student is to answer 8 out of 10 questions on the exam.
a) find the number n of ways the student can choose 8 out of 10 questions
b) find n if the student must answer the first three questions
c) How many if he must answer at least 4 of the first 5 questions?

Result

a =  45
b =  21
c =  35

Solution:

Solution in text a =
Solution in text b =
Solution in text c =







Leave us a comment of example and its solution (i.e. if it is still somewhat unclear...):

Showing 0 comments:
1st comment
Be the first to comment!
avatar




To solve this example are needed these knowledge from mathematics:

Would you like to compute count of combinations?

Next similar examples:

  1. Mumbai
    Mumbai A job placement agency in Mumbai had to send ten students to five companies two to each. Two of the companies are in Mumbai and others are outside. Two of the students prefer to work in Mumbai while three prefer to work outside. In how many ways assignment
  2. Trinity
    trojka How many different triads can be selected from the group 43 students?
  3. A book
    books_32 A book contains 524 pages. If it is known that a person will select any one page between the pages numbered 125 and 384, find the probability of choosing the page numbered 252 or 253.
  4. Fish tank
    zebra_fish A fish tank at a pet store has 8 zebra fish. In how many different ways can George choose 2 zebra fish to buy?
  5. The confectionery
    ice_cream The confectionery sold 5 kinds of ice cream. In how many ways can I buy 3 kinds if order of ice creams does not matter?
  6. First class
    prvni_jakost The shipment contains 40 items. 36 are first grade, 4 are defective. How many ways can select 5 items, so that it is no more than one defective?
  7. Disco
    vencek On the disco goes 12 boys and 15 girls. In how many ways can we select four dancing couples?
  8. Weekly service
    school_table.JPG In the class are 20 pupils. How many opportunities have the teacher if he wants choose two pupils randomly who will weeklies?
  9. Division
    skauti_3 Division has 18 members: 10 girls and 6 boys, 2 leaders. How many different patrols can be created, if one patrol is 2 boys, 3 girls and 1 leader?
  10. Theorem prove
    thales_1 We want to prove the sentense: If the natural number n is divisible by six, then n is divisible by three. From what assumption we started?
  11. Calculation of CN
    color_combinations Calculate: ?
  12. Count of triangles
    SquareTriangle Given a square ABCD and on each side 8 internal points. Determine the number of triangles with vertices at these points.
  13. 2nd class combinations
    color_circle From how many elements you can create 4560 combinations of the second class?
  14. Hockey
    hokej Hockey match ended 8:2. How many different matches could be?
  15. Blocks
    cubes3_1 There are 9 interactive basic building blocks of an organization. How many two-blocks combinations are there?
  16. One green
    gulicky In the container are 45 white and 15 balls. We randomly select 5 balls. What is the probability that it will be a maximum one green?
  17. Hearts
    hearts_cards 4 cards are chosen from a standard deck of 52 playing cards (13 hearts) with replacement. What is the probability of choosing 4 hearts in a row?