B) Three times a number minus 4 is four times the number plus 1. What is the number?

-5

Step-by-step explanation:

1) write it out:

3x-4=4x+1

2)combine like terms

The probability is 1/30 or 0.0333

Step-by-step explanation:

For calculating the probability we need to make a division between the number of ways in which the first boy born is named Sam and the second boy born is named Mark and the total number of ways in which the couple can name their children.

To calculate the total number of  ways in which the couple can name their children, we can use the rule of multiplication as:

         6             *              5                   =    30          

First boy Born       2nd Boy Born

Because we have 6 options for the name of the first boy and 5 options for the name of the second boy.

Additionally, In just one option from this 30, the first boy is named Sam and the second is named Mark.

So, the probability is calculate as the division between 1 and 30 as: