Answer:
2/15
Step-by-step explanation:
There is a 4/10 probability that she chooses blue the first time, but the second time it is a 3/9 chance because she didn't put the marble back so there are 9 marbles in total, 3 blue ones.
4/10 x 3/9 = 2/5 x 1/3 = 2/15
I hope this helps :)
Edit: Messed up the multiplication, whoops!
3/5=x
3÷x=5
multiply both sides by x
x(3÷x)=(5)x
cancel out x on the left side of the equation
3=5x
divide both sides by 5
3/5=(5x)/5
cancel out 5 on the right side
Therefore, the coefficient of is .