Mathematics - Online Test

Q1. If a line has the direction ratios – 18, 12, – 4, then what are its direction cosines ?
Answer : Option A
Explaination / Solution:

If a line has the direction ratios – 18, 12, – 4, then its direction cosines are given by:


Q2. In any ΔABC,ΔABC, the expression (a + b + c) (a + b – c) (b + c – a) (c + a – b) is equal to
Answer : Option C
Explaination / Solution:



Q3. The number of significant numbers which can be formed by using any number of the digits 0, 1, 2, 3, 4 but using each not more than once in each number is
Answer : Option C
Explaination / Solution:

Case 1: for 5 digit numbers Ten Tens thousands place can be occupied in 4 ways since 0 cannot be suitable. For ones place remaining 4 numbers ( since repetition is not allowed ) can be occupied in 4 ways : and the tens place in 3 ways and hundreds place in 2 ways and the thousands place in 1 way. Hence the total number of ways is 4x1x4x2x3= 96.

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Case 2: for 4 digit numbers thousands place can be occupied in 4 ways since 0 cannot be suitable. For ones place remaining 4 numbers ( since repetition is not allowed ) can be occupied in 4 ways : and the tens place in 3 ways and hundreds place in 2 ways . Hence the total number of ways is 4x4x2x3= 96.

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4234

Case 3: for 3digit numbers hundreds place can be occupied in 4 ways since 0 cannot be suitable. For ones place remaining 4 numbers ( since repetition is not allowed ) can be occupied in 4 ways : and the tens place in 3 ways  Hence the total number of ways is 4x4x3= 48

Case 4: for 2 digit numbers Tens place can be occupied in 4 ways since 0 cannot be suitable. For ones place remaining 4 numbers ( since repetition is not allowed ) can be occupied. Hence the total number of ways is 4x4=16.

Case 5: For single digit in 4 ways .

Hence 96 + 96 + 48+ 16+4 = 260


Q4. A point ( x , y , z ) moves parallel to X- axis . Which of the three variables x , y , z remain fixed ?
Answer : Option C
Explaination / Solution:

A point ( x , y , z ) moves parallel to X- axis then value of x will vary and remaining will be fixed

Q5. A square matrix is called an upper triangular if  for
Answer : Option A
Explaination / Solution:

Upper Triangular matrix is given by : Here,  if i is greater than j.and , if I is less than j.

Q6. If If  is a non real cube root of unity and then a and b are respectively the numbers :
Answer : Option B
Explaination / Solution:



Q7. If A and B are not disjoint Set , then n (A∪B) is equal to
Answer : Option A
Explaination / Solution:



Q8. The number of terms in the expansion of is
Answer : Option D
Explaination / Solution:



Q9. The area bounded by the parabola y =  + 1 and the straight line x + y = 3 is given by
Answer : Option B
Explaination / Solution:

The two curves parabola and the line meet where,
 3 - x =  = 0 .
Required area ;
 = 
Q10. Given that x is an integer, find the values of x which satisfy both 2x + 3 > 7 and x + 4 < 10
Answer : Option C
Explaination / Solution:


Since x is an integer the solution set 


Since x is an integer the solution set =


Hence the integer values which satisfy both the inequalities are