A binary number is represented by (cdccddcccddd)2, where c > d What is its decimal equivalent ?
1848
2048
2842
2872
Let S = {2, 4, 6, 8, ..........20}. What is the maximum number of subsets does S have ?
10
20
512
1024
Consider the following statements in respect of the quadratic equation 4(x - p)(x - q) - r2 = 0, where p, q and r are real numbers:
1) The roots are real
2) The roots are equal if p = q and r = 0
Where of the above statements is/are correct ?
1 only
2 only
Both 1 and 2
Neither 1 nor 2
C.
Both 1 and 2
Given equation 4(x - p)(x - q) - r2 = 0, where p, q and r are real numbers
Expand it: 4x2 – 4qx – 4px + 4pq – r2 = 0
It will became : 4x2 – 4(p + q) x + 4pq – r2 = 0
Now, check the discriminant (D)
D = 16[ - (p + q)]2 – 16(4pq – r2)
D = 16[p2 + q2 + 2pq – 4pq + r2]
D = 16[p2 + q2 - 2pq + r2]
D = 16[(p – q)2 + r2]
If p, q, r are real number then D > 0; hence roots will always be real
If p = q & r = 0 then D =0
Hence, both statement are correct.
Option C is correct.
How many real roots does the equation x2 + 3|x| + 2 = 0 have ?
1 only
2 Only
Both 1 and 2
Neither 1 nor 2
What is the solution of x ≤ 4, y ≥ 0 and x ≤ - 4, y ≤ 0 ?
x ≥ - 4, y ≤ 0
x ≤ 4, y ≥ 0
x ≤ - 4, y = 0
x ≥ - 4, y = 0
If 3rd, 8th and 13th terms of a GP are p, q and r respectively, then which one of the following is correct ?
q2 = pr
r2 = pq
pqr = 1
2q = p + r
Let Sn be the sum of the first n terms of an AP. If S2n = 3n + 14n2, then what is the common difference ?
5
6
7
9
Let a, b, c be in AP and k ≠ 0 be a real number. Which of the following are correct ?
1) ka, kb, kc are in AP
2) k –a, k -b, k –c are in AP
3) are in AP
Select the correct answer using the code given below :
1 and 2 only
2 and 3 only
1 and 3 only
1, 2 and 3