Let x be for unknown number. Let x be first number .
X+1 To be second number .x+2be third number. X+(x+1)+(x+2)=312.
Simplify to get 3x+3=312 . Subtract 3 from both sides 3x-3=312-3. Once you subtract get 3x=109.then divide 3 both sides . 3x/3=309/3. To get x= 103.
Now once you have that First number 103. Second number 103+1=104 . And third number 103+2=105. To check add them 103+104+105=312
The probability of pulling a purple marble is 4/7, since 4+3 is 7. Since the marbles are replaced, the probability does not change when pulling out marbles.
