Difficult word problem

Question

Three waiters at a local restaurant earned different amounts of money the past week. Jennifer earned $40 less than twice the amount tony earned. Chris earned $60 more than tony. How much did each waiter earn if they earned a total of $900?

Answer 1

1. Let J = the amount that Jennifer earned.  Let T = the amount Tony earned, and Let C = amount Chris earned
2. J = 2T - 40  {Eqn 1}
3. C = T + 60  {Eqn 2}
4. J+T+C = 900  {Eqn 3}
5. Three equations, three unknowns.  Solve by substitution
1. Substitute Eqn 1 and Eqn 2 into Eqn 3:   (2T-40) + T + (T+60) =900
2. 4T + 20 = 900
3. 4T = 880
4. T = 880/4 = 220
6. Now substitute the value of T back into Eqn 1 and Eqn 2
1. J = 2(220) - 40 =  440-40 = 400
2. C = 220 + 60 = 280
7. Final answer :  Jennifer earned $400, Chris earned $280 and Tony earned $220.
8. Doublecheck the work. 
1. Did Jennifer earn $40 less than twice what Tony earned?  Is $400 = (2*$220) - $40.   Yes, it is.
2. Did Chris earn $40 more than Tony?  Is $280 = $220 + $60.  Yes
3. Did they combine for $900?  Is $220 + $400 + $280 = $900.  Yes
4. It all checks out, so there were no math errors.