Question 1205707
<br>
The problem clearly involves solving a system of two linear equations; there are always a large number of choices of how to solve them.<br>
e = calories burned per minute on elliptical trainer
c = calories burned per minute on circuit training<br>
30e + 10c = 470
10e + 30c = 370<br>
With those two equations, my clear choice for a solution path is the following.<br>
Add the two starting equations and simplify:
40e + 40c = 840
10e + 10c = 210<br>
Compare that equation to each of the starting equations:<br>
20e = 260
20c = 160<br>
Solve:
e = 13
c = 8<br>
ANSWER: 13 calories per minute on the elliptical trainer; 8 per minute on the circuit training<br>
Obviously this solution method is only useful because of the exact numbers used... but it is a worthwhile thing to look out for in a problem like this.<br>