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  • Question
  • In a group of 6 boys and 4 girls, four children are to be selected. In how many different ways can they be selected such that at least one boy should be there?


  • Options
  • A. 209
  • B. 290
  • C. 200
  • D. 208

  • Correct Answer
  • 209 

    Explanation

    We may have (1 boy and 3 girls) or (2 boys and 2 girls) or (3 boys and 1 girl) or (4 boys). 

     

    Required number of ways =  6 C 1 * 4 C 3 + 6 C 2 * 4 C 2 + 6 C 3 * 4 C 1 + 6 C 4   

    6 C 1 * 4 C 1 + 6 C 2 * 4 C 2 + 6 C 3 * 4 C 1 + 6 C 2  = 209.


  • More questions

    • 1. What is the average of four tenths and five thousandths

    • Options
    • A. 25002
    • B. 2502
    • C. 0.2025
    • D. none
    • Discuss
    • 2. Which number will come in place of question mark 7, 16, 36, 78, 144, ?

    • Options
    • A. 168
    • B. 196
    • C. 222
    • D. 256
    • Discuss
    • 3. Seven years ago, the average age of A, B and C was 51 years. If A is 3 years older than B and B is 3 years older then C then the present ages of A, B and C are ( in year)

    • Options
    • A. 61, 58 and 55
    • B. 54, 51, and 48
    • C. 55, 58, and 61
    • D. 48, 51 and 54
    • Discuss
    • 4. In the given figure, PQRS is a square inscribed in a circle of radius 4 cm. PQ is produced till point Y. From Y a tangent is drawn to the circle at point R. What is the length (in cm) of SY ?

    • Options
    • A. 4√10
    • B. 2√10
    • C. 6√10
    • D. 3√5
    • Discuss
    • 5. If V = 12R / (r + R) , then R =

    • Options
    • A. Vr / (12 - V)
    • B. Vr + (V /12 )
    • C. V
    • D. V / (r - 12 )
    • Discuss
    • 6. In a class of 60 students there are 20 girls who scored an average of 40 marks in the test, what is the average marks of the boys if the class average is 60 marks?

    • Options
    • A. 60
    • B. 70
    • C. 50
    • D. D)
    • Discuss
    • 7. Which of the fractions given below, when added to 5/8, gives 1?

    • Options
    • A. 6/16
    • B. 5/2
    • C. 6/24
    • D. 6/3
    • Discuss
    • 8. LCM of 80, 85, 90

    • Options
    • A. 11440
    • B. 11998
    • C. 12240
    • D. 12880
    • Discuss
    • 9. In a triangle, the distance of the centroid from the three vertices is 4cm, 6cm and 8cm respectively. Then the length of the smallest median is:

    • Options
    • A. 8
    • B. 7
    • C. 6
    • D. 5
    • Discuss
    • 10. In a mixture of 25 litres, the ratio of milk to water is 4:1. Another 3 litres of water is added to the mixture. The ratio of milk to water in the new mixture is

    • Options
    • A. 5:1
    • B. 5:2
    • C. 5:3
    • D. 5:4
    • Discuss


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