Question

3
select the correct answer.
melissa exercises for 20 minutes every day. she decides to increase her daily exercise time by 5 minutes each week. however, according to her doctor’s orders, she can spend no more than 45 minutes a day exercising. for how many weeks can melissa increase her exercise time this way?
a. at least 13 weeks
b. at most 5 weeks
c. at most 13 weeks
d. at least 5 weeks

Explanation:

Step1: Define variables and inequality

Let \( w \) be the number of weeks. The initial time is 20 minutes, and she increases by 5 minutes per week, so the total time is \( 20 + 5w \). This must be less than or equal to 45 minutes (since she can spend no more than 45 minutes). So the inequality is \( 20 + 5w \leq 45 \).

Step2: Solve the inequality

Subtract 20 from both sides: \( 5w \leq 45 - 20 \) which simplifies to \( 5w \leq 25 \). Then divide both sides by 5: \( w \leq \frac{25}{5} \) so \( w \leq 5 \).

Answer:

B. at most 5 weeks