Question

harita must memorize 90 measures of music for her cello solo at a concert. she plans on memorizing 18 new measures for every 3 days of practice. which equation can be used to determine m, the number of measures harita still needs to memorize, as a function of d, the number of days of practice since she began learning the piece?
○ m = 72 - 15d
○ m = 90 - 6d
○ m = 101 - 21d
○ m = 108 - 3d

Explanation:

Step1: Calculate the number of measures memorized per day

She memorizes 18 measures in 3 days. So per - day memorization is $\frac{18}{3}=6$ measures per day.

Step2: Set up the linear equation

The initial number of measures to memorize is 90. After $d$ days, the number of measures she has memorized is $6d$. The number of measures she still needs to memorize $m$ is given by the formula \(m=\text{Initial number of measures}-\text{Number of measures memorized per day}\times d\). So \(m = 90-6d\)

Answer:

\(m = 90 - 6d\) (the second option)