Admas University Bishoftu Campus
College of Business and Management
Mathematics for Social Science
Assignment for BMGT Sections

1. Let [tex]$P(n): \frac{5n-6}{3}$[/tex] be an open sentence over the domain [tex]$Z$[/tex]. Determine, with explanations, whether the following statements are true or false:
a. [tex]$(\forall n \in Z) P(n)$[/tex]
b. [tex][tex]$(\exists n \in Z) P(n)$[/tex][/tex]

2. Give a formal proof to show that the following argument forms are valid:
[tex]$p \Rightarrow q, \neg r \Rightarrow \neg q \vdash \neg r \Rightarrow \neg p$[/tex]

3. A truck carries a load of 50 boxes; some are 20 kg boxes and the rest are 25 kg boxes. If the total weight of all boxes is 1175 kg, how many of each type are there?

4. The product of two numbers is 5. If their sum is 92, find the numbers.

5. Find the quotient and remainder and verify the Remainder Theorem by computing [tex]$p(a)$[/tex]:
a. Divide [tex]$p(x) = x^5 - 2x^2 - 3$[/tex] by [tex][tex]$x + 1$[/tex][/tex]

6. Determine the rational zeros of the polynomial [tex]$P(x) = 2x^3 - 5x^2 - 28x + 15$[/tex]

7. Evaluate the following limits, if they exist:
a. [tex]\lim_{x \rightarrow 2} \frac{x - 2}{\sqrt{x + 2} - 2}[/tex]
b. [tex]\lim_{x \rightarrow 1} \frac{\frac{1}{x} - 1}{x - 1}[/tex]
c. [tex]\lim_{x \rightarrow \infty} \frac{2x^3 + 3x - 5}{5x^3 + 1}[/tex]

8. Evaluate: [tex]\int \frac{x^3 - 4\sqrt{x}}{x^2} \, dx[/tex]

9.
a. Find the integral by the method of integration by parts: [tex]\int x^2 \sin x \, dx[/tex]
b. Find the area of the region under the graph of [tex]f[/tex] and the [tex]x[/tex]-axis on the given interval: [tex]f(x) = x^2 + 1[/tex] on [1, 3]

10. Use Cramer's rule (if possible) to solve the following linear systems:
[tex]\begin{cases}
4x_1^3 - 2x_2 + 3x_3 = -2 \\
2x_1 + 2x_2 + 5x_3 = 16 \\
8x_1 - 5x_2 - 2x_3 = 4
\end{cases}[/tex]



Answer :

Let's solve the question step-by-step.

Question 3:
A truck carries a load of 50 boxes; some are 20 kg boxes and the rest are 25 kg boxes. If the total weight of all boxes is 1175 kg, how many of each type are there?

Step-by-Step Solution:

1. Define Variables:
- Let [tex]\( x \)[/tex] be the number of 20 kg boxes.
- Let [tex]\( y \)[/tex] be the number of 25 kg boxes.

2. Write Equations:
We know that:
- The total number of boxes is 50:
[tex]\[ x + y = 50 \][/tex]
- The total weight of the boxes is 1175 kg:
[tex]\[ 20x + 25y = 1175 \][/tex]

3. Solve the System of Equations:
We have the following system of linear equations:
[tex]\[ \begin{cases} x + y = 50 \quad \text{(Equation 1)} \\ 20x + 25y = 1175 \quad \text{(Equation 2)} \end{cases} \][/tex]

4. Isolate One Variable:
From Equation 1, isolate [tex]\( y \)[/tex]:
[tex]\[ y = 50 - x \][/tex]

5. Substitute and Solve:
Substitute [tex]\( y = 50 - x \)[/tex] into Equation 2:
[tex]\[ 20x + 25(50 - x) = 1175 \][/tex]

6. Simplify and Solve for [tex]\( x \)[/tex]:
[tex]\[ 20x + 1250 - 25x = 1175 \][/tex]
[tex]\[ 20x - 25x + 1250 = 1175 \][/tex]
[tex]\[ -5x + 1250 = 1175 \][/tex]
[tex]\[ -5x = 1175 - 1250 \][/tex]
[tex]\[ -5x = -75 \][/tex]
[tex]\[ x = \frac{-75}{-5} \][/tex]
[tex]\[ x = 15 \][/tex]

7. Find [tex]\( y \)[/tex]:
Substitute [tex]\( x = 15 \)[/tex] back into the equation [tex]\( y = 50 - x \)[/tex]:
[tex]\[ y = 50 - 15 \][/tex]
[tex]\[ y = 35 \][/tex]

8. Conclusion:
Hence, the number of 20 kg boxes is [tex]\( 15 \)[/tex] and the number of 25 kg boxes is [tex]\( 35 \)[/tex].

Thus, the solution is [tex]\( 15 \)[/tex] boxes of 20 kg and [tex]\( 35 \)[/tex] boxes of 25 kg.