Math Quiz: Math for - Variables

  1. A storage bin for recycled materials initially holds $M$ kilograms of plastic. On Monday, $A$ kilograms of plastic are added to the bin. On Tuesday, $R$ kilograms of plastic are removed from the bin for processing.

    1. Write an algebraic expression for the final mass of plastic remaining in the bin.

    2. If the bin started with $M=250$ kg, $A=75$ kg were added, and $R=120$ kg were removed, calculate the final mass of plastic in the bin.

  2. A numerical value, let's call it $k$, is initially set to 15. The value of $k$ undergoes the following changes in sequence:

    1. Step 1: $k$ is replaced by $k - 7$.
    2. Step 2: The new value of $k$ is replaced by $k \times 3$.
    3. Step 3: The new value of $k$ is replaced by $k + 2$.

    What is the final value of $k$ after these three steps?

  3. A digital sensor measures a precise length as $L = 31.87$ centimeters. For a simplified report, the system records only the whole number part of this measurement, discarding the decimal part (truncation). What length value is recorded for the report?

  4. Let two numbers be $x = 10$ and $y = 4$. A new value $z$ is calculated using the formula $z = x \div y$. After $z$ is calculated, the value of $x$ is updated using the formula $x = x + z$. What are the final values of $x$, $y$, and $z$? (Note: $z$ can be a decimal number).

  5. An automated packaging system is designed to fill bags with rice. Each bag is intended to contain $S$ grams of rice. The system is set to fill a total of $N$ bags. The total amount of rice required, $T$, is calculated as $T = S \times N$.

    1. If each bag requires $S=750$ grams and the system is set to fill $N=30$ bags, what is the total amount of rice $T$ (in grams) needed?

    2. Suppose the machine has a total of $12000$ grams of rice available ($T=12000$). If each bag still requires $S=750$ grams, how many full bags ($N$) can be filled? (The number of bags must be a whole number, as a partially filled bag is not considered 'filled').