Skip to main content

Aptitude Day 124

Problems on Permutations and Combinations:

1. From a group of 4 men and 2 women, 3 persons are to be selected to form a committee so that at least 2 men are there on the committee. In how many ways can it be done?

Solution:
               =  4C2 *  2C1 + 4C3
               =  4C2 *  2C1 + 4C1
               =  (4*3)/(1*2) * 2 +
               = 12 +4
               = 16.

2. From a group of 6 boys and 3 girls, 5 children are to be selected. In how many different ways can they be selected such that at least 3 boys should be there?

Solution:
               = ( 6C3 * 3C2) + ( 6C4 *  3C1 ) +( 6C5 )
               = [(6*5*4)/(1*2*3) * 3C1] +[ 6C2 * 3 ] + 6C1
               = [20*3] +[(6*5/1*2)*3] +6
               = 60+45+6
               = 111.

Comments

Popular posts from this blog

Vocabulary Day 60

Incur Thesaurus: Verb :  arouse            acquire, earn, gain, include, get, obtain...  Antonyms :  lose, exclude ...  Example sentences:         ·        He is incurred in that game. ·        She incurs a great knowlegde in science.        

Vocabulary Day 82

Flutter Thesaurus: Verb: wave rapidly            drift, agitate, dance, flicker, fluctuate, hover, oscillate, quiver, shake, vibrate...                                           Antonyms:  stay, remain, stay . ..  Example sentences:         ·        His heart flutters when he sees his crush.  ·       That incident causes a  flutter between them. 

Aptitude Day 5

Answers of Day 4 :   1. 9                                   2. 5                                   3. 9                                   4. 8 To find the unit digit in the product. This is similar to the last model where we will find the unit digit of the sum. Example: 432*459*28*48=? Solution:  2*9=18 , 8*8=64, 4*8= 32. The unit digit of the total product is 2.  Problems to solve Find the unit digit of the product in the following 1. 404*397*810*21 =? 2. 24*42*36*78 =? 3. 81*82*89 =? 4. 72*36*98*47 =? See you tomorrow friends... Check out the answers over here  Aptitude Day 6