Math logic

There are 20 children in the group, each two children have a different name. Alena and John are among them. How many ways can we choose 8 children to be among the selected

A) was John
B) was John and Alena
C) at least one was Alena, John
D) maximum one was Alena, John?

Result

a =  50388
b =  18564
c =  75582
d =  196035840

Solution:    Leave us a comment of this math problem and its solution (i.e. if it is still somewhat unclear...): Be the first to comment! To solve this verbal math problem are needed these knowledge from mathematics:

Would you like to compute count of combinations?

Next similar math problems:

1. Blocks There are 9 interactive basic building blocks of an organization. How many two-blocks combinations are there?
2. Trinity How many different triads can be selected from the group 43 students?
3. Count of triangles Given a square ABCD and on each side 8 internal points. Determine the number of triangles with vertices at these points.
4. Confectionery The village markets have 5 kinds of sweets, one weighs 31 grams. How many different ways a customer can buy 1.519 kg sweets.
5. Weekly service In the class are 20 pupils. How many opportunities have the teacher if he wants choose two pupils randomly who will weeklies? On the menu are 12 kinds of meal. How many ways can we choose four different meals into the daily menu?
7. Hockey Hockey match ended 8:2. How many different matches could be?
8. Chords How many 4-tones chords (chord = at the same time sounding different tones) is possible to play within 7 tones?
9. Committees How many different committees of 6 people can be formed from a class of 30 students?
10. Examination The class is 21 students. How many ways can choose two to examination?
11. Calculation of CN Calculate: ?
12. 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 que
13. PIN - codes How many five-digit PIN - code can we create using the even numbers?
14. Theorem prove We want to prove the sentence: If the natural number n is divisible by six, then n is divisible by three. From what assumption we started?
15. First class 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?
16. Teams How many ways can divide 16 players into two teams of 8 member?
17. Commitee A class consists of 6 males and 7 females. How many committees of 7 are possible if the committee must consist of 2 males and 5 females?