Grade 8 Algebra: Word Problems: Functions

Name: ______________________Date: ____________Score: ____ / 8

Level 2

Interpret a function rule

1. Use ${C = 4h + 10}$ :
$C\text{}$ $\text{is}$ $\text{the}$ $\text{cost}$ $\text{in}$ $\text{dollars}$ $\text{to}$ $\text{rent}$ $\text{a}$ $\text{bike}$ $\text{for}$ $h\text{}$ $\text{hours.}$ $\text{What}$ $\text{do}$ $\text{the}$ $\text{4}$ $\text{and}$ $\text{the}$ $\text{10}$ $\text{mean?}$
2. Use ${T = 2m + 15}$ :
$T\text{}$ $\text{is}$ $\text{the}$ $\text{water}$ $\text{temperature}$ $\text{in}$ $\text{degrees}$ $\text{after}$ $m\text{}$ $\text{minutes}$ $\text{of}$ $\text{heating.}$ $\text{What}$ $\text{is}$ $\text{it}$ $\text{after}$ $\text{10}$ $\text{minutes?}$
3. Use ${d = 60t}$ :
$d\text{}$ $\text{is}$ $\text{the}$ $\text{distance}$ $\text{in}$ $\text{miles}$ $\text{a}$ $\text{train}$ $\text{goes}$ $\text{in}$ $t\text{}$ $\text{hours.}$ $\text{How}$ $\text{long}$ $\text{does}$ $\text{it}$ $\text{take}$ $\text{to}$ $\text{go}$ $\text{210}$ $\text{miles?}$
4. Use ${B = 500 - 25w}$ :
$B\text{}$ $\text{is}$ $\text{the}$ $\text{money}$ $\text{left}$ $\text{in}$ $\text{dollars}$ $\text{after}$ $w\text{}$ $\text{weeks.}$ $\text{After}$ $\text{how}$ $\text{many}$ $\text{weeks}$ $\text{is}$ $\text{the}$ $\text{money}$ $\text{gone?}$
5. Use ${P = 15n - 60}$ :
$P\text{}$ $\text{is}$ $\text{the}$ $\text{profit}$ $\text{in}$ $\text{dollars}$ $\text{from}$ $\text{selling}$ $n\text{}$ $\text{shirts.}$ $\text{How}$ $\text{many}$ $\text{shirts}$ $\text{must}$ $\text{be}$ $\text{sold}$ $\text{to}$ $\text{break}$ $\text{even?}$
6. Use ${H = 3w + 5}$ :
$H\text{}$ $\text{is}$ $\text{a}$ $\text{plant's}$ $\text{height}$ $\text{in}$ $\text{cm}$ $\text{after}$ $w\text{}$ $\text{weeks.}$ $\text{When}$ $\text{is}$ $\text{it}$ $\text{29}$ $\text{cm}$ $\text{tall?}$
7. Use ${C = 0.5m + 20}$ :
$C\text{}$ $\text{is}$ $\text{the}$ $\text{monthly}$ $\text{phone}$ $\text{cost}$ $\text{in}$ $\text{dollars}$ $\text{for}$ $m\text{}$ $\text{minutes.}$ $\text{What}$ $\text{is}$ $\text{the}$ $\text{cost}$ $\text{for}$ $\text{100}$ $\text{minutes?}$
8. Use ${V = 1200 - 150y}$ :
$V\text{}$ $\text{is}$ $\text{a}$ $\text{laptop's}$ $\text{value}$ $\text{in}$ $\text{dollars}$ $\text{after}$ $y\text{}$ $\text{years.}$ $\text{What}$ $\text{is}$ $\text{it}$ $\text{worth}$ $\text{after}$ $\text{4}$ $\text{years?}$

Answer Key

Level 2

1. $\$4\text{/hour; }\$10\text{ fee}$
2. $35^\circ$
3. $3.5\text{ hours}$
4. $20\text{ weeks}$
5. $4\text{ shirts}$
6. $8\text{ weeks}$
7. $\$70$
8. $\$600$

Grade 8 Algebra: Word Problems: Functions

Name: ______________________Date: ____________Score: ____ / 8

Level 3

Build the function

1. Solve:
$\text{A}$ $\text{gym}$ $\text{charges}$ $\text{a}$ $\text{40}$ $\text{dollar}$ $\text{joining}$ $\text{fee}$ $\text{plus}$ $\text{25}$ $\text{dollars}$ $\text{per}$ $\text{month.}$ $\text{Write}$ $\text{a}$ $\text{function}$ $\text{for}$ $m\text{}$ $\text{months}$ $\text{and}$ $\text{find}$ $\text{the}$ $\text{cost}$ $\text{for}$ $\text{1}$ $\text{year.}$
2. Solve:
$\text{A}$ $\text{tank}$ $\text{holds}$ $\text{90}$ $\text{liters}$ $\text{and}$ $\text{drains}$ $\text{6}$ $\text{liters}$ $\text{per}$ $\text{minute.}$ $\text{Write}$ $\text{a}$ $\text{function}$ $\text{for}$ $t\text{}$ $\text{minutes}$ $\text{and}$ $\text{find}$ $\text{when}$ $\text{it}$ $\text{is}$ $\text{empty.}$
3. Solve:
$\text{A}$ $\text{4}$ $\text{mile}$ $\text{taxi}$ $\text{ride}$ $\text{costs}$ $\text{11}$ $\text{dollars}$ $\text{and}$ $\text{a}$ $\text{10}$ $\text{mile}$ $\text{ride}$ $\text{costs}$ $\text{23}$ $\text{dollars.}$ $\text{Write}$ $\text{a}$ $\text{linear}$ $\text{function}$ $\text{for}$ $\text{the}$ $\text{cost}$ $\text{of}$ $m\text{}$ $\text{miles.}$
4. Solve:
$\text{A}$ $\text{plant}$ $\text{is}$ $\text{8}$ $\text{cm}$ $\text{tall}$ $\text{after}$ $\text{2}$ $\text{weeks}$ $\text{and}$ $\text{14}$ $\text{cm}$ $\text{tall}$ $\text{after}$ $\text{5}$ $\text{weeks.}$ $\text{Write}$ $\text{a}$ $\text{function}$ $\text{for}$ $w\text{}$ $\text{weeks}$ $\text{and}$ $\text{find}$ $\text{its}$ $\text{height}$ $\text{at}$ $\text{planting.}$
5. Solve:
$\text{Plan}$ $\text{A}$ $\text{costs}$ $\text{30}$ $\text{dollars}$ $\text{plus}$ $\text{5}$ $\text{dollars}$ $\text{per}$ $\text{class.}$ $\text{Plan}$ $B\text{}$ $\text{costs}$ $\text{10}$ $\text{dollars}$ $\text{per}$ $\text{class.}$ $\text{For}$ $\text{how}$ $\text{many}$ $\text{classes}$ $\text{do}$ $\text{they}$ $\text{cost}$ $\text{the}$ $\text{same?}$
6. Solve:
$\text{A}$ $\text{car}$ $\text{has}$ $\text{50}$ $\text{liters}$ $\text{of}$ $\text{fuel}$ $\text{and}$ $\text{uses}$ $\text{4}$ $\text{liters}$ $\text{every}$ $\text{50}$ $\text{km.}$ $\text{How}$ $\text{much}$ $\text{fuel}$ $\text{is}$ $\text{left}$ $\text{after}$ $\text{300}$ $\text{km?}$
7. Solve:
$\text{An}$ $\text{empty}$ $\text{bucket}$ $\text{weighs}$ $\text{2}$ $\text{kg}$ $\text{and}$ $\text{each}$ $\text{liter}$ $\text{of}$ $\text{water}$ $\text{adds}$ $\text{1}$ $\text{kg.}$ $\text{Write}$ $\text{a}$ $\text{function}$ $\text{for}$ $x\text{}$ $\text{liters}$ $\text{and}$ $\text{find}$ $\text{the}$ $\text{weight}$ $\text{with}$ $\text{7}$ $\text{liters.}$
8. Solve:
$\text{A}$ $\text{printer}$ $\text{warms}$ $\text{up}$ $\text{for}$ $\text{1}$ $\text{minute,}$ $\text{then}$ $\text{prints}$ $\text{18}$ $\text{pages}$ $\text{per}$ $\text{minute.}$ $\text{How}$ $\text{many}$ $\text{pages}$ $\text{are}$ $\text{printed}$ $\text{in}$ $\text{6}$ $\text{minutes?}$

Answer Key

Level 3

1. $C = 25m + 40;\ \$340$
2. $V = 90 - 6t;\ 15\text{ min}$
3. $C = 2m + 3$
4. $H = 2w + 4;\ 4\text{ cm}$
5. $6\text{ classes}$
6. $26\text{ L}$
7. $W = x + 2;\ 9\text{ kg}$
8. $90\text{ pages}$

Word Problems: Functions: Classroom Packet

Grade 8 Algebra: Word Problems: Functions

Level 1

Answer Key

Level 1

Grade 8 Algebra: Word Problems: Functions

Level 2

Answer Key

Level 2

Grade 8 Algebra: Word Problems: Functions

Level 3

Answer Key

Level 3