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: Find the number of measures memorized per day

She memorizes 18 measures every 3 days. So the number of measures memorized per day is $\frac{18}{3}=6$.

Step2: Set up the function

She started with 90 measures to memorize. The number of measures she has memorized after $d$ days is $6d$. So the number of measures $m$ she still needs to memorize is $m = 90-6d$.

Answer:

B. $m = 90 - 6d$