Sandra earns $100 more than John if they both earn $3000 how much do they each earn

Question

Presently doing algebra equations and expressions not sure as to how to begin to answer the question if i should use x as an unknow etc

Answer 1

You can solve this by treating it as a system of equations:

Let S represent Sandra's earnings and J represent John's earnings

S + J = 3000 (equation 1)
J = S - 100 (equation 2)

Substitute equation 2 for equation 1:

 

S + S - 100 = 3000

 

Simplifying and solving for S:

 

2S = 3100

 

S = 1550

 

Going back to the equation for J:

J = 1550 - 100 = 1450