Question

Cards numbered from 1 to 70 are mixed up and placed in a box. Then a card is drawn at random. What is the probability that the card drawn will have a number with the same digit for both the ones place and the tens place? Write your answer as a decimal rounded to the nearest thousandth.

Answer 1

Hey,

→ Cards numbered : 1 to 70

=> Total Possible Events = 70

→ Desired Event is : the number is divisible by 11 

=> Total such events = n{ 11 , 22 , 33 , 44 , 55 , 66 } = 6

=> Probability of Event = n( E ) ÷ n( S ) = ( 6 ) ÷ ( 70 )

=> P( E ) = 0.0857 ≈ 0.086 

Answer 2

{11,22,33,44,55,66}/70
=6/70
=.086