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?
Answer
A
m is equal to 72 minus 15 d
B
m is equal to 90 minus 6 d
C
m is equal to 101 minus 21 d
D
m is equal to 108 minus 3 d
Explanation
Harita memorizes 18 measures in 3 days, so her rate is 18 ÷ 3 = 6 measures per day. She starts with 90 measures to learn, and the number remaining decreases by 6 for each day of practice. Therefore, m = 90 − 6d, which is choice B, “m is equal to 90 minus 6d.”
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