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Zorluk: OrtaSystems of Linear Inequalities in Two Variables

A delivery driver is loading a van with small boxes and large boxes. Each small box weighs 1010 pounds, and each large box weighs 3535 pounds. The total weight of the boxes in the van cannot exceed 1,0001,000 pounds. The driver must load at least 44 times as many small boxes as large boxes. If the driver loads at least 1010 large boxes, what is the maximum number of large boxes that the driver can load?

Cevap: 13

Cevap

13
To find the maximum number of large boxes, yy, we set up the system of inequalities: 10x+35y100010x + 35y \le 1000 and x4yx \ge 4y. To maximize yy, we minimize xx by setting x=4yx = 4y. Substituting this into the weight constraint gives 10(4y)+35y100010(4y) + 35y \le 1000, which simplifies to 75y100075y \le 1000, or y13.33y \le 13.33. The largest integer satisfying this inequality is 13, which also satisfies y10y \ge 10.

Adım Adım Çözüm

1
Define variables for the quantities of each type of box.
Let xx be the number of small boxes and yy be the number of large boxes, where xx and yy are non-negative integers.
Establishing variables is necessary to translate the verbal constraints into algebraic inequalities.
2
Translate the given constraints into a system of linear inequalities.
The weight limit gives 10x+35y100010x + 35y \le 1000. The requirement for at least 4 times as many small boxes as large boxes gives x4yx \ge 4y. The minimum of 10 large boxes gives y10y \ge 10.
Representing the scenario mathematically allows us to find the boundaries of the solution set.
3
Express the weight inequality in terms of a single variable by using the boundary condition of the second inequality.
To maximize yy, we want to minimize the weight contributed by the small boxes, xx. The minimum value of xx for any yy is x=4yx = 4y. Substituting x=4yx = 4y into the weight inequality gives 10(4y)+35y100010(4y) + 35y \le 1000.
Finding the extreme case (minimum number of small boxes) provides the upper limit for the number of large boxes.
4
Simplify the inequality and solve for yy.
40y+35y1000    75y1000    y10007513.3340y + 35y \le 1000 \implies 75y \le 1000 \implies y \le \frac{1000}{75} \approx 13.33.
This calculation determines the upper algebraic bound for the number of large boxes.
5
Determine the maximum integer value for yy that satisfies the system.
Since the number of boxes must be an integer, the maximum integer value less than or equal to 13.3313.33 is 1313. Since 131013 \ge 10, this satisfies all constraints.
Real-world quantities like boxes must be whole numbers, so we take the largest integer within the solution set.

Anahtar Kavram

Solving systems of linear inequalities in two variables to optimize a value under constraints.
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