Answer:
D. 21/2
Step-by-step explanation:
We simply have to evaluate the first three terms based on the progression's formula:
t= 1, the first term is 8, as we see:

t=2, the second term is 2, as we see:

t=3, the third term is 1/2, as we see:

The sum of the first 3 terms is then: 8 + 2 + 1/2 = 10 1/2
Among the answer choices, D. 21/2, which is 10 1/2.
Answer:
138 degrees
Step-by-step explanation:
Angle b and the 42 degree angle right next to it are supplementary angles. That means that 42+b=180
b=138
The standard form: Ax + By = C
y = 90 - 15x <em>add 15x to both sides</em>
<h3>15x + y = 90</h3>
Multiply 2 2/4 by 5/8.
First, simplify 2 2/4 to 2 1/2.
Then, convert to improper form (5/2).
5/2 x 5/8 = 25/16
answer: 1 9/16 gallons of water