$79.74083 is the answer hope i help you
i divided 956.89 in 12 so that was the answer
You're looking for a value

such that

Because the distribution is symmetric, the value of

in either case will be the same.
Now, because the distribution is continuous, you have that

The mean for the standard normal distribution is

, and because the distribution is symmetric about its mean, it follows that

.

You can consult a

score table to find the corresponding score for this probability. It turns out to be

.
Answer: a) 0.7
b) 70%
Step-by-step explanation:
a) There are 10 marbles.The red marbles are 7
so that 7/10
then change to decimal 7/10=0.7
b) if we get percentage *100
so, 7÷10*100%
70%