# Help with system of equations: using profits

#### notgoodatmath

##### New member
I've been having a difficult time with system of equations I was wondering if I could have some assistants with system of equations. Here's the question

Question: Keller industries' profits were up $20,000 this year over last year. This was an increase of 25%. a. Let T represent the profit this year and L the profit from last year and write a system of equations that can be used to determine the profits. b. Which method would be most efficient to solve this system (addition method or substitution method)? Explain c.Using your system to determine the profit for this year and last year. Two pieces of information are given: ∙ This year's profit is$20000 more than last year's profit.
∙ The increase is 25%.
You should write both in equation form. Then you get a system of two equations with two variables, which you can solve.

But how do i write the equations?
I have a few thoughts.

#### SuperSonic4

##### Well-known member
MHB Math Helper
I've been having a difficult time with system of equations I was wondering if I could have some assistants with system of equations. Here's the question

Question: Keller industries' profits were up $20,000 this year over last year. This was an increase of 25%. a. Let T represent the profit this year and L the profit from last year and write a system of equations that can be used to determine the profits. b. Which method would be most efficient to solve this system (addition method or substitution method)? Explain c.Using your system to determine the profit for this year and last year. Two pieces of information are given: ∙ This year's profit is$20000 more than last year's profit.
∙ The increase is 25%.
You should write both in equation form. Then you get a system of two equations with two variables, which you can solve.

But how do i write the equations?
I have a few thoughts.
What thoughts have you had? Do you know how to express percentage increases?

#### notgoodatmath

##### New member
What thoughts have you had? Do you know how to express percentage increases?
Not exactly because i'm not sure were exactly to start. I know theirs two equations on for one year with a 200,000 increase than last year which was 25% more. But I don't understand where to start the problem? Is their two equations?

#### SuperSonic4

##### Well-known member
MHB Math Helper
Not exactly because i'm not sure were exactly to start. I know theirs two equations on for one year with a 200,000 increase than last year which was 25% more. But I don't understand where to start the problem? Is their two equations?
There will be two equations - Part A pretty much tells you it's needed: One will be the absolute increase (20,000) and the other will be the percentage increase (25%)

For the first equation: This year's profit (T) is going to be last year's profit (L) + any extra (20,000).

For the second equation: T will be L multiplied by 1+%change/100 (25%)