Answer :
Given:
Amount of money previously saved = $ 150.
Amount of money saved from tutoring job per hour = $ 10.
Required:
( a ) Total amount of money saved after tutoring for 12 hours.
( b ) expression to represent the total amount of money Mikaila saved after working for x hours.
( c ) Inequality to determine the minimum number of hours.
( d ) Compound inequality to determine the number of hours Mikaila needs to tutor to have enough money in her savings account to purchase a laptop that costs at least $550 but not more than $1,1550.
Explanation:
( a ) Amount of money saved after tutoring for 12 hours is calculated as,
[tex]Money\text{ saved due to tutoring = 12 }\times\text{ 10 = \$ 120}[/tex]Total amount of money saved = $ 150 + $ 120 = $ 270
Thus the total amount of money saved after tutoring for 12 hours is $ 270.
( b ) The amount of money saved after tutoring for x hours is calculated as,
[tex]After\text{ x hours of tutoring = 10x}[/tex]Total amount of money saved after x hours = 10x + $ 150.
Thus the total amount of money saved after tutoring for x hours is 10x + $ 150.
( c ) The required inequality is calculated as,
[tex]Inequality\text{ = 10x + 150 }\ge\text{ 550}[/tex]Inequality representing the minimum number of hours required to purchase a laptop for $ 150 or more is calculated as,
[tex]\begin{gathered} 10x\text{ + 150 }\ge\text{ 550 } \\ 10x\text{ + 150 - 150 }\ge\text{ 550 - 150} \\ 10x\text{ }\ge\text{ 400} \\ x\text{ }\ge\text{ 40} \end{gathered}[/tex]( d ) In inequality represents the number of hours Mikaila needs to work to purchase a laptop that costs more than or equal to $ 150 and less than or equal to $ 1150 is calculated as,
[tex]\begin{gathered} 1150\ge10x\text{ + 150}\ge550 \\ \end{gathered}[/tex]On solving,
[tex]\begin{gathered} 1150\text{ }\ge\text{ 10x + 150} \\ 1150\text{ - 150 }\ge\text{ 10x + 150 - 150} \\ 1000\text{ }\ge\text{ 10x } \\ 100\ge x \\ x\text{ }\leq\text{ 100} \end{gathered}[/tex]Further,
[tex]\begin{gathered} 10x\text{ + 150 }\ge\text{ 550} \\ 10x\text{ + 150 - 150 }\ge\text{ 550 - 150} \\ 10x\text{ }\ge\text{ 400} \\ x\text{ }\ge\text{ 40} \end{gathered}[/tex]Thus the required inequality representing the number of hours is
[tex]40\leq x\leq100[/tex]Answer:
(a) Total amount of money saved after tutoring for 12 hours is $ 270.
(b) Expression to represent the total amount of money Mikaila saved after working for x hours is 10x + $ 150.
(c) Inequality to determine the minimum number of hours for purchasing the laptop for $ 550 or more.
[tex]x\ge40[/tex](d) Compound inequality to determine the number of hours Mikaila needs to tutor to have enough money in her savings account to purchase a laptop that costs at least $550 but not more than $1,1550 is,
[tex]40\leq x\leq100[/tex]