## Algebra: A Combined Approach (4th Edition)

Using the formula T = 50 + $\frac{N - 40}{4}$, substitute the value given into the equation. 55 = 50 + $\frac{N - 40}{4}$ Solve for N: 5 = $\frac{N - 40}{4}$ 20 = N - 40 60 = N Interpret: 60 chirps per minute