26.5 goes in the first box
The answer is 689.
Answer:



And in the figure attached we see the limits with the percentages associated.
Step-by-step explanation:
For this case we know that the random variable of interest is the scores on a test given to all juniors in a school district follows a normal distribution with the following parameters:

For this case we know from the empirical rule that within one deviation from the mean we have approximately 68.2% of the data, within 2 deviations from the mean we have 95% and within 3 deviation 99.7%
We can find the limits and we got:



And in the figure attached we see the limits with the percentages associated.
Answer:
52 cards:
26 red and 26 black
P(R) = probability of picking a red card
P(B) = probability of picking a black card
P(R) = P(B) = ¹/₂
If with replacement:
P(R∩B) = (¹/₂)(¹/₂) = ¹/₄
If without replacement:
P(R∩B) = (¹/₂)(²⁶/₅₁) = ¹³/₅₁
8 Balls:
3 red and 5 white
P(R) = probability of picking a red ball
P(W) = probability of picking a white ball
P(R) = ³/₈
P(W) = ⁵/₈
If with replacement:
P(R∩W) ∪ P(W∩R) = (³/₈)(⁵/₈) + (⁵/₈)(³/₈)
= ¹⁵/₆₄ + ¹⁵/₆₄
= ³⁰/₆₄
= ¹⁵/₃₂
If without replacement:
P(R∩W) ∪ P(W∩R) = (³/₈)(⁵/₇) + (⁵/₈)(³/₇)
= ¹⁵/₄₂ + ¹⁵/₄₂
= ³⁰/₄₂
= ⁵/₇