simple probability question

questionrobability of getting 7 at least once when pair of dice is tossed twice (so it mean probability of getting 7 in one dice and also on other dice).
how can i approach this.we know probability of getting 7 in when two dice thrown is 6/36 .For throwing twice we cant say 12/36.can we?

bhuvaneshnick said:

questionrobability of getting 7 at least once when pair of dice is tossed twice (so it mean probability of getting 7 in one dice and also on other dice).

Click to expand...

In order to "get 7 in one dice", the number 7 would have to be on one side of a die. Are these not the regular cubes, with pips for 1, 2, 3, 4, 5, and 6 on their sides?

What is the exact text of the exercise? Are you maybe supposed to toss two regular dice at the same time, and then find the sum of the values displayed on the two dice? And then toss the two regular dice again, and find the sum again? And then figure out the probability of getting a sum of 7 once or twice (but not never)?

If so, then you have two independent events. What is the probability of getting a sum of 7 on one throw? Then what is the probability of getting a 7 on a second throw? Given that these are independent, how should you work with these probabilities? (Hint: How do you work with the probabilities when tossing fair coins?)

bhuvaneshnick said:

we know probability of getting 7 in when two dice thrown is 6/36 .For throwing twice we cant say 12/36.can we?

Click to expand...

If you would think about what you are saying then you cn conclude that you are not correct. Follow this simple logic
Throw two dice once--prob is 6/36
Throw two dice twice--prob is 12/36
Throw two dice three times--prob is 18/36
Throw two dice four times--prob is 24/36
Throw two dice five times--prob is 30/36
Throw two dice six times--prob is 36/36 = 1

Do you really think that if you throw a pair of dice 6 times then it is certain that you will get a sum of 7 each time?
If you throw the two dice 7 times then the prob will be 42/36 which is greater than 1?
Also, do you really think that the probability will increase as you throw the pair of dice more and more?