Answer:

Step-by-step explanation:
For this case we want to find this probability:

Because they want the area to the left of the value. We need to remember that the normal standard distribution have a mean of 0 and a deviation of 1.
We can use the following excel code: =NORM.DIST(-1.55,0,1,TRUE)
And we got:

The other possibility is use the normal standard table and we got a similar result.
Answer:
1) x-axis 2) y-axis
Step-by-step explanation:
The first two options imply that x can be somewhere *between* -2 and 4, which clearly isn’t the case. Looking at the two sections graphed, we see that x can be less than, but not equal to, -2 (indicated by the hollow dot at -2) and greater than *or* equal to 4 (indicated by the solid dot at 4). The third option is the only one that describes this situation.
10a + 8b = 230
a + b = (2 + 2 + 13 + 10)...a + b = 27 (this is the number of gifts to buy)
a = 27 - b
10(27 - b) + 8b = 230
270 - 10b + 8b = 230
-10b + 8b = 230 - 270
-2b = -40
b = -40/-2
b = 20 <=== she bought 20 eight dollar gifts
a = 27 - b
a = 27 - 20
a = 7 <=== she bought 7 ten dollar gifts
2. is the answer B
3. is the answer D
4. is the answer C
5.B
6. A