Question a-sale

5.1 Linear Inequalities in One or Two Variables - Compound inequalities
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A salesperson’s total earnings consist of a base salary of x dollars per year, plus commission earnings of 11 % of the total sales the salesperson makes during the year. This year, the salesperson has a goal for the total earnings to be at least 3 times and at most 4 times the base salary. Which of the following inequalities represents all possible values of total sales s , in dollars, the salesperson can make this year in order to meet that goal? 

A.

2 x ≤s≤ 3 x

B.

20.11x≤s≤30.11x

C.

3 x ≤s≤ 4 x

D.

30.11x≤s≤40.11x

A salesperson’s total earnings consist of a base salary of x dollars per year, plus commission

Hard-difficulty · SAT Math · Linear Inequalities in One or Two Variables — Compound inequalities. Read the question above, select your answer, and check the full explanation below to understand exactly why the correct choice works.

Answer explanation

Choice B is correct. It’s given that a salesperson's total earnings consist of a base salary of x dollars per year plus commission earnings of 11% of the total sales the salesperson makes during the year. If the salesperson makes s dollars in total sales this year, the salesperson’s total earnings can be represented by the expression x+0.11s. It’s also given that the salesperson has a goal for the total earnings to be at least 3 times and at most 4 times the base salary, which can be represented by the expressions 3 x and 4 x , respectively. Therefore, this situation can be represented by the inequality 3x≤x+0.11s≤4x. Subtracting x from each part of this inequality yields 2x≤0.11s≤3x. Dividing each part of this inequality by 0.11 yields 20.11x≤s≤30.11x. Therefore, the inequality 20.11x≤s≤30.11x represents all possible values of total sales s , in dollars, the salesperson can make this year in order to meet their goal.

Choice A is incorrect. This inequality represents a situation in which the total sales, rather than the total earnings, are at least 2 times and at most 3 times, rather than at least 3 times and at most 4 times, the base salary.

Choice C is incorrect. This inequality represents a situation in which the total sales, rather than the total earnings, are at least 3 times and at most 4 times the base salary.

Choice D is incorrect. This inequality represents a situation in which the total earnings are at least 4 times and at most 5 times, rather than at least 3 times and at most 4 times, the base salary.