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- Question
An urn contains 4 white 6 black and 8 red balls . If 3 balls are drawn one by one without replacement, find the probability of getting all white balls.
Options- A. 5/204
- B. 1/204
- C. 13/204
- D. None of these
- Correct Answer
- 1/204
ExplanationLet A, B, C be the events of getting a white ball in first, second and third draw respectively, then
Required probability =
=
Now, P(A) = Probability of drawing a white ball in first draw = 4/18 = 2/9
When a white ball is drawn in the first draw there are 17 balls left in the urn, out of which 3 are white
Since the ball drawn is not replaced, therefore after drawing a white ball in the second draw there are 16 balls left in the urn, out of which 2 are white.
Hence the required probability =
- 1. The banker's discount on a bill due 4 months hence at 15 % is Rs. 420. What is the true discount?
Options- A. Rs. 410
- B. Rs. 400
- C. Rs. 390
- D. Rs. 380 Discuss
- 2. In a two-digit number, the digit at the unit's place is 1 less than twice the digit at the ten's place. If the digits at unit's and ten's place are interchanged, the difference between the new and the original number is less than the original number by 20. The original number is
Options- A. 47
- B. 59
- C. 23
- D. 35 Discuss
- 3. The last digit of the number obtained by multiplying the numbers 41 x 42 x 43 x 44 x 45 x 46 x 47 x 48 x 49 will be?
Options- A. 0
- B. 1
- C. 4
- D. 5 Discuss
- 4. The average age of 24 students in a class is 10. If the teacher's age is included, the average increase by one . The age of the teacher is?
Options- A. 25 year
- B. 30 year
- C. 35 year
- D. 40 year Discuss
- 5. What is the place value of '6' in the number 4562304?
Options- A. Thousand
- B. Hundred
- C. Ten Thousand
- D. Lakh Discuss
- 6. When 1? 7 of the number is subtracted from the number itself, it gives the same value as the sum of all the angles of a triangle. What is the number?
Options- A. 224
- B. 210
- C. 140
- D. 350 Discuss
- 7. The product of two consecutive number odd number is 6723. What is the greater number?
Options- A. 89
- B. 85
- C. 91
- D. 83 Discuss
- 8. How many rational numbers are there between 1 and 1000?
Options- A. 998
- B. 999
- C. 1000
- D. infinite Discuss
- 9. The sum of 5 consecutive even numbers A, B, C, D and E is 130. What is the product of A and E?
Options- A. 720
- B. 616
- C. 660
- D. 672 Discuss
- 10. The local value of 7 in the numeral 5679032 is?
Options- A. 7
- B. 70000
- C. 10000
- D. 5070000 Discuss
More questions
Correct Answer: Rs. 400
Explanation:
Given in the question,
Banker's Discount = 420
Time in years = 4 months = 4/12 years = 1/3 years
Rate of interest = 15 %
As we know the formula,
True Discount = Banker's Discount × 100 (100 + Time in years x Rate of interest )
True Discount = 420 × 100 (100 + 4/12 × 15) ( 12 Months = 1 Year)
= 420 × 100 (100 + 5) = 400
Correct Answer: 47
Explanation:
Since two digit number = 10p + q
According to question , ? q = 2p ? 1.. (i)
When digits are interchanged then new number = 10q + p
then original number ? [new number ? original number] = 20
? 10p + q ? [10q + p ? (10p + q)] = 20
? 10p + q ? 10q ? p + 10p + q = 20
19p ? 8q = 20
19p ? 8 (2p ? 1) = 20 (Using eq. (i))
19p ? 16p + 8 = 20
3p = 12 ? p = 4
From (i) q = 2 × 4 ? 1 ? q = 7
? original number = 10p + q = 10 × 4 + 7 = 47
Correct Answer: 0
Explanation:
Last digit will be multiplication of 1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9.
It includes 5 & 2.
So, 5 x 2=10,
0 will be the last digit.
Correct Answer: 35 year
Explanation:
Age of the teacher = Sum of age of 24 students and teacher - Sum of age of 24 students.
= 25 x 11 - 24 x 10
= 35 years.
? Age of teacher = 35 years.
Correct Answer: Ten Thousand
Explanation:
Position value of 6 = 10000
Correct Answer: 210
Explanation:
Let number be the x.
According to the equation , x - x?7 = 180
? 6x?7 = 180
? x = 210
Correct Answer: 83
Explanation:
Let the two consecutive odd number be (x + 1) and (x + 3).
According to question (x + 1) (x + 3) = 6723
? x2 + 3x + x + 3 = 6723
? x2 + 4x + 3 = 6723
? x2 + 4x - 6720 = 0
? x2 + 84x - 80x - 6720 = 0
? ( x - 80 )( x + 84 )= 0
? x = 80, (x ? -84)
Hence, the greater number = 80 + 3 = 83
Correct Answer: infinite
Explanation:
There can be infinite number of rational numbers between 1 and 1000.
Correct Answer: 660
Explanation:
Let 5 consecutive even number be A = x, B = x+2, C = x+4, D = x + 6 and E = x + 8.
According to question
x + x +2 + x + 4 + x + 6 + x + 8 = 130
? 5x + 20 = 130
? x = 22
? A = 22, E = 22 + 8 = 30.
? Multiplication of A and E = 22 x 30
= 660
Correct Answer: 70000
Explanation:
The local value of 7 in 5679032 is 70000.
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