Can someone, anyone, help me with this?

Here’s the answer sorry if it’s hard to read

1.       Given numbers:
=> $8 per hour by tutoring
=> $7.50 per hour by walking the dogs
=> You have 15 hours available
=> You need to make atleast $115 in walking the dogs.

let’s assign a variable to use.
Let a = tutoring
Let b = walking the dogs
=> a + b = 15
=> 8a + 7.5b = 115
=> 8a + 7.5(15 - a) = 115
=> 8a = 112.5 = 115
=> 8a = 115 – 112.5
=> 8a = 2.5
=> 8a / 8 = 2.5 / 8
=> a = 0.3125
=> b = 15 – 0.3125
=> b = 14.6875