Answer:
Tina can select and answer the essay questions on her test in 35 ways.
Step-by-step explanation:
The order in which she chooses the questions is not important. For example, choosing questions 1, 3 and 7 is the same as choosing 7, 3 and 1. So we use the combinations formula to solve this question.
Combinations formula:
is the number of different combinations of x objects from a set of n elements, given by the following formula.

In this question:
Three questions from a set of 7. So

Tina can select and answer the essay questions on her test in 35 ways.
Answer: 7x + 70
Step-by-step explanation:
Answer:

Step-by-step explanation:
Let x represent the number of lawns Jacob mowed and y represent the number of dogs Sarah walked.
Jacob charges $20 each time he mows a lawn, then he earns $20x for x lawns mowed.
Sarah charges $10 each time she walks a dog, then she earns $10y for y dogs walked.
In total, they will earn $(20x + 10y). They need at least $2000 in order to go on a trip, then

Note that 
One the first problem on finding the constant of <span> proportionality in this situation the answer is 2. Below is the solution:
constant = unit rate
unit rate = $2/ poung
K = 2
For the second question, the equation is the below:
T = 2p or y = 2x</span>