7 is

miles; the question includes the words "in all", which shows that the two fractions should be added together. To add fractions with the same denominator, you must simply add the numerators and keep the denominator unchanged.
8 is

yards of ribbon; this one also requires you to add the fractions-- the numerators should be added, but the denominator stays the same because the two fractions share the same denominator.
Answer:
b) Chemistry
Step-by-step explanation:
To compare both scored we need to standardize the scores using the following equation:

Where x is the score, m is the mean and s is the standard deviation. So, 82 on chemistry is equivalent to:

Because the mean of the scores on the chemistry final exam is equal to 75 and the standard deviation is 15
At the same way, 80 on Calculus is equivalent to:

Because the mean of the scores on the calculus final exam is equal to 83 and the standard deviation is 13
Now, we can compare the values. So, taking into account that -0.2308 is lower than 0.4667, we can said that the student do better in Chemistry.
Answer:
44%
Step-by-step explanation:
For these types of problems, look at the totals. We know that there are 0.44 out of 1 eighth graders. Since it doesn't specify how the 8th grader is dropped off, we take 0.44 and divide it by 1 (the total). We get 0.44, but since it's most likely asking for percentages, multiply that by 100.
Answer:
Option D
Step-by-step explanation:
a/3 = 8/6
a × 6 = 8 × 3
6a = 24
a = 24/6
a = 4
Hence,
Option A is correct