Question

A desk and a chair cost $200 as a set. If the desk costs four times more than the chair, how much does each one cost. Write and solve using a system of equations.

Answer 1

d = desk
c = chair

Equation:
d + c = 200
d = 4c

Answer 2

Substitute 4c for d in first equation and solve for c. Insert that value into the second equation and solve for d. Check by inserting both values into the first equation.