Question

Arianna is working two summer jobs, making $6 per hour walking dogs and making $10 per hour tutoring. In a given week, she can work at most 11 total hours and must earn at least $80.

Answer 1

Step-by-step explanation:

x = number hours dog walking

y = number hours tutoring

x + y <= 11

6x + 10y >= 80

the solution is the common area below the first line and above the second line.

the first line is above the second line (due to the y-intercept of 11 vs. 8) until the crossing point.

for the crossing point we use the regular equations :

from the first we get

x = 11 - y

using this in the second

6×(11 - y) + 10y = 80

66 - 6y + 10y = 80

4y = 14

y = 14/4 = 7/2 = 3.5

x = 11 - y = 11 - 3.5 = 7.5

so, she has to do at least 3.5 hours tutoring (and then 7.5 hours dog walking) for the minimum of $80 earning, all the way up to the maximum of 11 hours tutoring (and 0 dog walking) for $110 earning.