Question

i need help. Semir, Sarah, and SungSo decided to raise money for a local homeless shelter by working in a local deli. The deli agreed to donate to the shelter a portion of the profits from each meal the three sold. Semir sold 3 times as many meals as Sarah. SungSo sold 2 more meals than Sarah.The three decided to participate in a walkathon to raise additional money for the shelter. Sarah walked 5 miles less than twice the number of miles that Semir walked. They each collected $18 in pledges for every mile they walked.                                                                                    a.Let n represent the number of miles Semir walked. Write an expression for the number of miles Sarah walked and an expression for the amount of money Sarah collected in pledges

Answer 1

According to the question, 
Let,
"n" represent the number of miles semir walked.
"y" represent the number of miles sarah walked.
Now, according to the question,

y = 2n - 5  ........................this is your equation 
Also,
the question states, each of them collect $18 in pledges for every miles walked.

Given,
Sarah collected $450
Now, 

Using unitary method,

Sarah collects $18 for 1 mile
Sarah collects $1 for (1 / $18) mile
Sarah collects $450 for (1 / 18) * 450 mile
                                   = 25 miles
So, Sarah walks 25 miles.
Now,
Taking equation,
y = 2n - 5
Since, y is the no. of miles sarah walked, we can write 25 in place of "y" So,
(25) = 2n - 5
25 + 5 = 2n
30 = 2n
30 / 2 = n
15 = n

Since, "n" is the no. of miles that semir walked, Semir walked 15 miles.