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If n ≠ 3k and 1 ,ω,ω2 are the cube roots of unity then has the value
Del=(1-w^3n)+w^n(0)+w^2n(w^4n-w^n) =1-(w^3)^n+(w^6)^n-(w^3)^n =1-1+1-1 =0
If , then its value is equal to
x,y,z being +ive equals
The number of values of k for which the system of equations ( k+1)x + 8y = 4k, kx + (k+3)y = 3k - 1 has inifinitely many solutions is
For infinitely many solutions the two equation become identical.
Let . Then A is
IF B is a non-singular matrix and A is a square matrix, then det (B-1 AB)
will be equal to
Two cards are drawn at random and without replacement from a pack of 52 playing cards. Find the probability that both the cards are black.
Seven chits are numbered 1 to 7. Three are drawn one by one with replacements. The probability that the least number on any selected chit is 5, is
A student appear for tests I,II and III. The student is successful if he passes either in tests I and II or tests I and III. The probabilities of the student passing in tests I,II and III are p,q and 1/2 respectively. If the probability that the student is successful is 1/2, then
Words from the letters of the word PROBABILITY are formed by talking all at a time.The probability that both B’s are together & both I’s are together is
The probability that a person will hit a target in a shooting practice is 0.3. If the shoots 10 times, the probability that he hit the target is
The probability that Krishna will be alive 10 years hence is 7/15 and that Hari will be alive is 7/10. What is the probability that both Krishna and Hari will be dead 10 years hence
Value of is
Value of odd order skew symmetric determinant
If then value of (a + b) = ?
Three children are selected at random from a group of 6 boys and 4 girls. It is known that in this group exactly one girl and one boy belong to same parents. The probability that the selected group of children have no blood relations, is equal to?
P(boy and his sister both are selected)
∴ Required probability
= 1 – 1/15 = 14/15 = 0.93
The probability that the 13th day of a randomly chosen month is a Friday, is?
Probability of selecting a month = 1/12.
13th day of a randomly selected month is Friday if its first day is Sunday.
Probability of this event = 1/7.
Hence required probability = 0.01
If two integers m and n are chosen at random from 1 to 100 then the probability that a number of the form 7m + 7n is divisible by 5 equals:
Since m and n are selected between 1 and 100, hence sample space = 100 × 100
Also, 71 = 7, 72 = 49, 73 = 343, 74 = 2401,
75 = 16807 etc. Hence 1, 3, 7 and 9 will be the last digits in the powers of 7.
n, m →
1,1 1,2 1,3 ........... 1, 100
2,1 2,2 2,3 ........... 2, 100
100, 1 100,2 100, 3......... 100, 100
For m = 1 ; n = 3, 7, 11, ...... 97
∴ Favourable cases = 25
For m = 2, n = 4, 8, 12, ......., 100
∴ Favourable cases = 25
Similarly for every m, favourable n are 25.
∴ Total favourable cases = 100 × 25
Hence required probability =