logo

CuriousTab

CuriousTab

Discussion

Home ‣ Aptitude ‣ Probability See What Others Are Saying!
  • Question

  • Two cards are drawn at random from a pack of 52 cards.what is the probability that either both are black or both are queen?


  • Options
  • A. 52/221
  • B. 55/190
  • C. 55/221
  • D. 19/221

  • Correct Answer
  • 55/221 

    Explanation

    We have n(s) = 52 C 2 52 = 52*51/2*1= 1326. 

    Let A = event of getting both black cards 

         B = event of getting both queens 

    A?B = event of getting queen of black cards 

    n(A) = 52 * 51 2 * 1  =  26 C 2  = 325, n(B)= 26 * 25 2 * 1 = 4*3/2*1= 6  and  n(A?B) =  4 C 2  = 1 

    P(A) = n(A)/n(S) = 325/1326;

    P(B) = n(B)/n(S) = 6/1326 and 

    P(A?B) = n(A?B)/n(S) = 1/1326 

    P(A?B) = P(A) + P(B) - P(A?B) = (325+6-1) / 1326 = 330/1326 = 55/221

    • More questions

    • 1. 
      A certain distance is covered at a certain speed. If half of this distance is covered in double the time, the ratio of the two speed is?

    • Options
    • A. 4:1
    • B. 1.4
    • C. 2:1
    • D. 1:2
      • Discuss
    • 2. 
      The length of the train that takes 8 second to pass a pole where it runs at a speed of 36 km/hr is?

    • Options
    • A. 288 meters
    • B. 45 meters
    • C. 48 meters
    • D. 80 meters
      • Discuss
    • 3. Two goods train each 500 m long, are running in opposite directions on parallel tracks. Their speeds are 45 km/hr and 30 km/hr respectively. Find the time taken by the slower train to pass the driver of the faster one.

    • Options
    • A. 12 sec
    • B. 24 sec
    • C. 48 sec
    • D. 60 sec
      • Discuss
    • 4. A jogger running at 9 kmph alongside a railway track in 240 metres ahead of the engine of a 120 metres long train running at 45 kmph in the same direction. In how much time will the train pass the jogger?

    • Options
    • A. 3.6 sec
    • B. 18 sec
    • C. 36 sec
    • D. 72 sec
      • Discuss
    • 5. A train 108 m long moving at a speed of 50 km/hr crosses a train 112 m long coming from opposite direction in 6 seconds. The speed of the second train is:

    • Options
    • A. 48 km/hr
    • B. 54 km/hr
    • C. 66 km/hr
    • D. 82 km/hr
      • Discuss
    • 6. Two stations A and B are 110 km apart on a straight line. One train starts from A at 7 a.m. and travels towards B at 20 kmph. Another train starts from B at 8 a.m. and travels towards A at a speed of 25 kmph. At what time will they meet?

    • Options
    • A. 9 a.m.
    • B. 10 a.m.
    • C. 10.30 a.m.
    • D. 11 a.m.
      • Discuss
    • 7. Two goods train each 500 m long, are running in opposite directions on parallel tracks. Their speeds are 45 km/hr and 30 km/hr respectively. Find the time taken by the slower train to pass the driver of the faster one.

    • Options
    • A. 12 sec
    • B. 24 sec
    • C. 48 sec
    • D. 60 sec
      • Discuss
    • 8. When a plot is sold for Rs. 18,700, the owner loses 15%. At what price must that plot be sold in order to gain 15%?

    • Options
    • A. Rs. 21,000
    • B. Rs. 22,500
    • C. Rs. 25,300
    • D. Rs. 25,800
      • Discuss
    • 9. If x and y are the two digits of the number 653xy such that this number is divisible by 80, then x + y =?

    • Options
    • A. 2 or 6
    • B. 4
    • C. 4 or 8
    • D. 8
    • E. None of these
      • Discuss
    • 10. The difference of the squares of two consecutive odd integers is divisible by which of the following integers?

    • Options
    • A. 3
    • B. 6
    • C. 7
    • D. 8
      • Discuss

    Comments

    There are no comments.
Enter a new Comment




Aptitude

Engineering

Programming

Reasoning

Links

Copyright ©CuriousTab. All rights reserved.