Checking account earnings at Long's Bank are expressed by the equation, I=−0.06x+8.3

The earnings at Fellow's Bank are modeled by I=−0.02x+6.6
.

In both cases, x is the number of checks written.

For what range of checks will a checking account at Long's Bank generate more earnings income than one at Fellow's Bank? Show your work or explain how you got your answer

1 answer

To find the range of checks for which a checking account at Long's Bank generates more earnings income than at Fellow's Bank, we need to compare the two equations and solve for x.

I = -0.06x + 8.3 (Earnings at Long's Bank)
I = -0.02x + 6.6 (Earnings at Fellow's Bank)

We can set the two equations equal to each other to find the break-even point:

-0.06x + 8.3 = -0.02x + 6.6

Now, we can solve for x:

-0.06x + 0.02x = 6.6 - 8.3
-0.04x = -1.7
x = (-1.7)/(-0.04)
x = 42.5

Therefore, Long's Bank will generate more earnings income than Fellow's Bank if the number of checks written is greater than 42.5. However, since we cannot have half a check, we take the range to be x > 42.