Answer
f = 7.5 and i = 21.25
Steps Explained:
Use the substitution method to solve:
15f + 6i = 240
Check Format
Equation 2 is in the correct format.
Rearrange Equation 2 to solve for f:
15f + 6i = 240
Subtract 6i from both sides to isolate f:
15f + 6i - 6i = 240 - 6i
15f = 240 - 6i
Now divide by 15:
| 15f | |
| 15 |
| = |
| 240 - 6i |
| 15 |
Plug Revised Equation 2 value into f:
12(f) + 8i = 260
12 * ((240 - 6i)/15) + 8i = 260
((2880 - 72i)/15) + 8i = 260
Multiply equation 1 through by 15
15 * (((2880 - 72i)/15) + 8i = 260)
15 * (((2880 - 72i)/15) + 8i = 260)
2880 - 72i + 120i = 3900
Group like terms:
-72i + 120i = 3900 - 2880
48i = 1020
Divide each side by 48
| 48i | |
| 48 |
| = |
| 1020 |
| 48 |
| i = | 1020 |
| 48 |
i = 21.25
Plug this answer into Equation 1
12f + 8(21.25) = 260
12f + 170 = 260
12f = 260 - 170
12f = 90
Divide each side by 12
| 12f | |
| 12 |
| = |
| 90 |
| 12 |
| f = | 90 |
| 12 |
f = 7.5
Related Calculators: Equation and Inequalities | Literal Equations | Find two numbers word problems
Math is always fascinating! Have you noticed? On the path to discovering the ultimate mysteries of math, we move forward with small steps.
Many such discoveries of mathematical formulas validate the research efforts of those who came before us. If you want to inspire yourself and those around you, try making your own Custom Enamel Badges of achievement for small accomplishments.
These vivid pin badges can be a constant reminder that numbers aren't exactly cold and that they can always be accompanied by fun and hope.
