Question

marta 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 she 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 = 103 - 3d

Explanation:

Step1: Calculate measures memorized per day

She memorizes 18 measures every 3 days. So per day, she memorizes $\frac{18}{3}=6$ measures.

Step2: Find remaining measures formula

She has to memorize 90 measures in total. After $d$ days, the number of measures she has memorized is $6d$. So the number of measures $m$ she still needs to memorize is $m = 90-6d$.

Answer:

m = 90 - 6d (corresponding to the second option in the multiple - choice list)