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Carly tutors students in math on the weekends and offers both thirty-minute sessions and sixty-minute sessions. She earns \[tex]$15 for each thirty-minute session and \$[/tex]25 for each sixty-minute session.

If she earned \[tex]$230 this past weekend and had $[/tex]x[tex]$ thirty-minute sessions and $[/tex]x-2[tex]$ sixty-minute sessions, what is the value of $[/tex]x$?

A. 5
B. 8
C. 6
D. 7


Sagot :

Sure, let's determine the value of [tex]\( x \)[/tex] step by step:

1. Identify the earnings for each session:
- Carly earns \[tex]$15 for each 30-minute session. - Carly earns \$[/tex]25 for each 60-minute session.

2. Set up the total earnings equation:
- Let [tex]\( x \)[/tex] be the number of 30-minute sessions Carly had.
- Thus, she had [tex]\( x - 2 \)[/tex] 60-minute sessions.

3. Formulate the earnings equation:
- The earnings from [tex]\( x \)[/tex] 30-minute sessions: [tex]\( 15x \)[/tex] dollars.
- The earnings from [tex]\( x - 2 \)[/tex] 60-minute sessions: [tex]\( 25(x-2) \)[/tex] dollars.
- The total earnings are given as \$230.

4. Set up the equation:
- The total amount Carly earned can be represented as:
[tex]\[ 15x + 25(x - 2) = 230 \][/tex]

5. Simplify and solve for [tex]\( x \)[/tex]:
- Expand the equation:
[tex]\[ 15x + 25x - 50 = 230 \][/tex]
- Combine like terms:
[tex]\[ 40x - 50 = 230 \][/tex]
- Add 50 to both sides:
[tex]\[ 40x = 280 \][/tex]
- Divide both sides by 40:
[tex]\[ x = 7 \][/tex]

Therefore, the value of [tex]\( x \)[/tex] is:

[tex]\[ \boxed{7} \][/tex]