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14. Mary is taking a Mathematics test and must answer at least 20 problems correctly to earn the grade she wants. Mary knows she answered 5 problems correctly and uses [tex]\( c \)[/tex] to represent the remaining problems she must answer correctly. Which inequality best represents this situation?

A. [tex]\( 5 - c \geq 20 \)[/tex]

B. [tex]\( 5 + c \geq 20 \)[/tex]

C. [tex]\( 5 - c \leq 20 \)[/tex]

D. [tex]\( 5 + c \leq 20 \)[/tex]

16. Roberto had [tex]\( \$20 \)[/tex]. He bought a soccer ball that cost [tex]\( m \)[/tex] dollars. He now has less than [tex]\( \$5 \)[/tex] left. Which inequality represents this situation?

A. [tex]\( 20 - m \ \textless \ 5 \)[/tex]

B. [tex]\( 20 - m \ \textgreater \ 5 \)[/tex]

C. [tex]\( m - 20 \ \textless \ 5 \)[/tex]

D. [tex]\( m - 20 \ \textgreater \ 5 \)[/tex]

18. The cost of renting a boat is [tex]\( \$20 \)[/tex] plus [tex]\( \$2.50 \)[/tex] per hour, where [tex]\( x \)[/tex] is the number of hours of boat rental. Millie wants to spend less than [tex]\( \$50 \)[/tex] on the boat rental. Which inequality models this situation?

A. [tex]\( 20x + 2.50 \ \textgreater \ 50 \)[/tex]

B. [tex]\( 20x + 2.50 \ \textless \ 50 \)[/tex]

C. [tex]\( 20 + 2.50x \ \textgreater \ 50 \)[/tex]

D. [tex]\( 20 + 2.50x \ \textless \ 50 \)[/tex]


Sagot :

Let's solve each of these problems step-by-step.

### Question 14:
Mary must answer at least 20 problems correctly to get the grade she wants. She already knows she answered 5 problems correctly. We need to find out the remaining problems she needs to answer correctly, which we'll represent with [tex]\( c \)[/tex].

Since the total number of problems she answers correctly will be the sum of the problems she already answered (5) and the problems she needs to answer ([tex]\( c \)[/tex]), the inequality that describes this situation is:
[tex]\[ 5 + c \geq 20 \][/tex]

Thus, the best representation of this situation is:
B. [tex]\( 5 + c \geq 20 \)[/tex]

### Question 16:
Roberto started with [tex]$20. He bought a soccer ball that cost \( m \) dollars. After this purchase, he has less than $[/tex]5 left.

The amount of money Roberto has left after buying the soccer ball is calculated by subtracting the cost of the soccer ball ([tex]\( m \)[/tex]) from his initial amount ([tex]$20). This remaining amount must be less than $[/tex]5, so we write:
[tex]\[ 20 - m < 5 \][/tex]

Thus, the inequality representing this situation is:
A. [tex]\( 20 - m < 5 \)[/tex]

### Question 18:
The cost of renting a boat is [tex]$20 plus an additional $[/tex]2.50 per hour represented by [tex]\( x \)[/tex]. Millie wants to keep the total cost of renting the boat under [tex]$50. The total cost of the boat rental is the fixed cost ($[/tex]20) plus the hourly cost ([tex]$2.50 for each hour \( x \)). Millie wants this total cost to be less than $[/tex]50, so we get:
[tex]\[ 20 + 2.50x < 50 \][/tex]

Thus, the inequality modeling this situation is:
D. [tex]\( 20 + 2.50x < 50 \)[/tex]