Latest TCS Aptitude Question SOLUTION: If ‘n‘ integers taken at random and multiplied together, then what is the probability that the last digit of the product is 1, 3, 7 or 9 ?

• Placement Papers
• /
• TCS
• /
• undefined

TCS Question Papers: TCS Interview Experience(90) TCS Company Profile

(#M40039907) TCS question Keep an EYE

If ‘n‘ integers taken at random and multiplied together, then what is the probability that the last digit of the product is 1, 3, 7 or 9 ?

Asked In TCS Koyel K (9 years ago)

Solved Sitanshu Shukla Read Solution (5)

Is this Puzzle helpful?   (6)   (1) Submit Your Solution undefined

Read Solution (5) :

Sitanshu Shukla  (9 years ago) Best Solution

Ans: (2/5)^n
Last digit may be 0,1,2,3,4,5,6,7,8,9 = 10
condition is 1,3,7,9 = 4
and n random no. so
probability is 4^n/10^n=(4/10)^n=(2/5)^n

Is this solution Helpfull? Yes (22) | No (1)  

Aastha  (9 years ago)

probability will be 4/10 or 2/5
as last digit can be any no between 0 to 9
no of total cases will be 10
prob=4/10

Is this solution Helpfull? Yes (9) | No (1)  

dhirender kalra  (9 years ago)

as the last digit can be only when multipied with 1 only so the are only 4 no. out 10 so P is 2/5

Is this solution Helpfull? Yes (3) | No (1)  

Thalamanchi Kishan Kumar  (9 years ago)

If the last digit in the product is to 1,3,7,9 the last digit in all n numbers should not be 0 and 5 and last digit of all numbers should not be selected exclusively from the set of numbers 2,4,6,8
favourable no. of cases=(8^n)-(4^n)
but generally last digit can be anyone of 0,1,2,3,4,5,6,7,8,9
so,total no. of ways =10^n
prob={(8^n)-(4^n)}/(10^n)

Is this solution Helpfull? Yes (1) | No (1)  

Aman Yadav  (9 years ago)

2n/5n
There a 4 probable case of these numbers so 4n/10n and n be any random integer

Is this solution Helpfull? Yes | No   

Please Login to Read Solution.