Sets, Relations and Functions Chapter 7 Exercise 7C CA foundation maths solutions
CA foundation maths solutions for Chapter 7 Exercise 7C Sets Relations and Functions are given.
First you should study the CA maths textbook lesson chapter 7 Seta, Relations and Functions very well.
You must observe and practice all examples which are given in the textbook.
You can observe the solutions given below. You will be try them in your own way.
Sets, Relations and Functions
Exercise 7C
CA maths solutions Sets , Relations and Functions Chapter 7 Exercise 7C
CA foundation maths solutions
Chapter 7
Sets Relations and Functions
Exercise 7C
Questions and solutions
1. “Is smaller than” over the set of eggs in a box is
Solution:
If a is smaller than b and b is smaller than c. Therefore a is smaller than c.
Therefore it is transitive (T)
2. “Is equal to” over the set of all rational numbers is
Solution:
a is equal to a. Therefore it is reflexive. It is symmetric as well as transitive.
Therefore it is equivalence. (E)
3. “has the same father as” over the set of children.
Solution;
None of given options.
4. “is perpendicular to over” the set of straight lines in a given plane is
Solution;
If a line a is perpendicular to line b. The line b is also perpendicular to line a.
Thereforeo it is symmetric. (S)
If a line a is perpendicular to line b and a line b is perpendicular to line c. Therefore line a will be parallel to line c not perpendicular .
Therefore it is not transitive.
5. “is the reciprocal of” ………. over the set of non zero real numbers is
Solution:
A number cannot be reciprocal of itself except 1.
Therefore, it is not reflexive.
If a is a reciprocal of b then b is reciprocal of a.
Therefore, it is symmetric. (S)
6. {(x, y)/y = x} is
Solution;
{(x, y)/ y = x}
If x = y
If x = y, y = x,
If x = y, y = z, then z = x
the relation is reflexive, symmetric and transitive.
Therefore, it is an equivalence. (E)
7. { (x, y)/x + y = 2x where x and y are positive integers }, is
Solution;
x + y = 2x, then y = 2x
Therefore, the relation is reflexive, symmetric and transitive.
Therefore, it is an equivalence. (E)
8. “Is the square of” over n set of real numbers is
Solution:
A number cannot be square of itself except 1. Therefore it is not reflexive.
If a is square is of b then b cannot be square of a. There for it is not symmetric.
If a is square of b and b is square of c. Then a cannot be square of c. Therefore, it is not transitive.
None of the options.
10. In a group of 20 children, 8 drink tea but not coffee and 13 like tea. The number of children drinking coffee but not tea is
11. The number of subsets of these set {6, 8, 11} is.
13. If the universal set E = {x | x is a positive integer < 25 }, A = { 2, 6, 8, 14, 22 }, B = { 4, 8, 10, 14 } then
Chapter 7 Exercise 7C solutions CA maths solutions Sets, Relations and Functions
14. If the set P has 3 elements Q four and R two then set P × Q × R contains
16. A town has a total population of 50,000. Out of it 28,000 read the newspaper X under 23,000 read Y 4,000 read both the papers. The number of persons not reading X and Y both is
17. If A = { 1, 2, 3, 5, 7 } and B = {1, 3, 6, 10, 15 }. Cardinal number of A – B is
18. Which of the diagram is graph of a function.
a. 
b.
c.
d.
Solution:
The relation must be one to one for the function.
For one to one function from the graphs draw the lines parallel to Y axis and it to intersect the graph in one point. (b)
19. At a certain conference of 100 people there are 29 Indian women and 23 Indian men. Out of these Indian people 4 are doctors and 24 are either men or doctors. There are no foreign doctors. The number of women doctors attending the conference is
20. Let A = {a, b}. Set of subset of A is called power set of A denoted by P(A). Now n[P(A)] is
21. Out of 2000 employees in an and office 48% preferred Coffee (c), 54% liked (T), 64% used to smoke (S). Out of the total 28% used C and T, 32% used T and S and 30% preferred C and S only 6% did none of these. The number having all the three is
22. Out of 2000 employees in an and office 48% preferred Coffee (c), 54% liked (T), 64% used to smoke (S). Out of the total 28% used C and T, 32% used T and S and 30% preferred C and S only 6% did none of these. The number of employees having T and S but not C is
23. Out of 2000 employees in an and office 48% preferred Coffee (c), 54% liked (T), 64% used to smoke (S). Out of the total 28% used C and T, 32% used T and S and 30% preferred C and S only 6% did none of these. The number of employees preferring only coffee is
Note : You can observe the solutions and try them in your own method.