Tag: mathematics and statistics

Questions Related to mathematics and statistics

Multiple choice mathematics and statistics introduction to set union and intersections union and intersection of sets basic operations on sets

In a class of $80$ children, $35$% children can play only cricket, $45$% children can play only table-tennis and the remaining children can play both the games. In all, how many children can play cricket?

  1. $55$
  2. $44$
  3. $36$
  4. $28$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

n(Children who can play only cricket) $ = 35\% = 80\times \dfrac{35}{100} = 28$

n(Children who can play only table tennis) $ = 45\% = 80\times \dfrac{45}{100} = 36$

$n(C \cap T) = 80-28-36 = 16$

n(Children can play cricket) $= 28+16 =44$

Multiple choice mathematics and statistics introduction to set union and intersections union and intersection of sets basic operations on sets

If x belongs to set of integers, A is the solution set of $2(x-1)< 3x-1$ and B is the solution set of $4x-3\leq 8+x$, find A$\cap$B.

  1. $\left\{0, 1, 2\right\}$
  2. $\left\{1, 2, 3\right\}$
  3. $\left\{0, 1, 2, 3\right\}$
  4. $\left\{0, 2, 4\right\}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
$2(x-1)< 3x-1$
$\Rightarrow 2x-2< 3x-1$
$\Rightarrow 2x-3x< -1+2$
$\Rightarrow -x< 1$
$\Rightarrow x> -1$

$4x-3\leq 8+x$
$4x-3-x+3\leq 8+x-x+3$
$\Rightarrow 4x-x\leq 8+3$
$\Rightarrow 3x\leq 11$
$x\leq \dfrac{11}{3}\Rightarrow x\le 3.67$
Then $-1< x\leq 3.67$
Then, $A\cap B$ is $ \{0,1,2,3 \}$
Multiple choice mathematics and statistics introduction to set union and intersections union and intersection of sets basic operations on sets

If $A = \left {2, 3, 4, 8, 10\right }, B = \left (3, 4, 5, 10, 12\right }, C = \left {4, 5, 6, 12, 14\right }$, then $(A\cap B)\cup (A\cap C)$ is equal to

  1. $\left \{3, 4, 10\right \}$
  2. $\left \{2, 9, 10\right \}$
  3. $\left \{4, 5, 6\right \}$
  4. $\left \{3, 5, 14\right \}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$ A={2,3,4,8,10} , B={3,4,5,10,12} , C={4,5,6,12,14}$


To find : $(A\cap B)$ $\cup  (A\cap C)$

$A\cap B$ = elements common in sets $A$ and $B$. 
$A\cap C$ = elements common in sets $A$ and $C$ 

$A\cap C = \{4\}$ 
$(A\cap B)\cup (A\cap C)=$elements in $(A\cap B)$ and $(A\cap C)$
$(A\cap B) \cup  (A\cap C) = \{3,4,10\} \cup \{4\} $
$(A\cap B) \cup  (A\cap C)={3,4,10}$

Multiple choice mathematics and statistics introduction to set union and intersections union and intersection of sets basic operations on sets

If $aN=\left{ ax:x\epsilon N \right}$, then the set $3N\cap 7N$ is

  1. $21\ N$
  2. $10\ N$
  3. $4\ N$
  4. None of these

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The set nN represents multiples of n. The intersection of multiples of 3 (3N) and multiples of 7 (7N) consists of multiples of the least common multiple of 3 and 7, which is 21. Thus, 3N intersect 7N = 21N.

Multiple choice mathematics and statistics introduction to set union and intersections union and intersection of sets basic operations on sets

A is a set containing $n$ elements. $A$ subset $P$ of $A$ is chosen. the set $A$ is reconstructed by replacing the elements of $P.A$ subset $Q$ of $A$ is again chosen. the number of ways of choosing $P$ and $Q$ so that $P \cap Q$

  1. $9. ^{n}C _{2}$
  2. $3^{n}- ^{n}C _{2}$
  3. $^{n}C _{2}.3^{n-2}$
  4. $4^{n}-3^{n}$
Reveal answer Fill a bubble to check yourself
A Correct answer