Word Problems enable us to see how systems of equations are nesessary in todays life. |
Example 1 |
|
| Legolas and Gimili need to destroy 380 Uraki in 40 minutes at Helms Deep. Gimili destroys 8 Uraki in a minute and Legolas destroys 12 in a minute. How long should each one fight? | |
| Determine
the equations. Let "l" stand for Legolas and
"g" for Gimili.
|
l+g=40 12l+8g=380 |
| Choose
what method would be best suited for this problem.
|
Substitiution |
| Get l
alone.
|
l=40-g |
| Plug the
equation from the last step into the second equation.
|
12(40-g)+8g=380 |
| Solve
for g
|
g=25 |
| Plug 25
into the first equation and solve for l.
|
l+25=40 l=15 |
| Your answer is... | Legolas
should spend 15 minutes on the battle field while Gimili needs to spend 25 minutes on the battlefield. |