Question :

There are two covers A and B; each containing paper slips with natural numbers from 1 to 7 written on them. One slip is drawn from each cover. Using them, a two digit number is formed with a number from A in the units place and the number from B in the tens place. How many such two digit numbers can be formed? What is the probability that a two digit number so formed is even?
Submitted on 4/2/2024 | Answered by Vandana Rana

Answer :


Number of slip in cover A = 7

Numbers of slips in cover B = 7


Numbers formed with a number from cover A in the units place and a number from cover B in the tens place are as follows:



11 12 13 14 15 16 17

21 22 23 24 25 26 27

31 32 33 34 35 36 37

42 42 43 44 45 46 47

51 52 53 54 55 56 57

61 62 63 64 65 66 67

71 72 73 74 75 76 77



Thus, total number of two digit numbers
= 7 ×7 = 49


Number of two digit even numbers
= 7 × 3 = 21


P(two digit number so formed is even)
=21/49

=3/7