Question

One pen costs \(\$\)0.25 and one marker costs \(\$\)0.35. At those prices, what is the total cost of 18 pens and 100 markers? 
 

Hint:

Recognizing that $0.25 is equivalent to the fraction 1/4 can make multiplication much faster than dealing with decimals. Multiplying by 100 simply involves moving the decimal point two places to the right.

Answer 1

Step 1: Understanding the Concept:

To find the total cost, we need to calculate the cost for all the pens and the cost for all the markers separately, and then add these two amounts together.

Step 2: Key Formula or Approach:

The formula to calculate the total cost is:

\[ \text{Total Cost} = (\text{Number of Pens} \times \text{Cost per Pen}) + (\text{Number of Markers} \times \text{Cost per Marker}) \] 

Step 3: Detailed Explanation:

Calculate the cost of the pens:

There are 18 pens, and each costs $0.25.

\[ \text{Cost of Pens} = 18 \times 0.25 \]

Since \( 0.25 = \frac{1}{4} \), the calculation becomes:

\[ \text{Cost of Pens} = 18 \times \frac{1}{4} = \frac{18}{4} = 4.50 \]

Calculate the cost of the markers:

There are 100 markers, and each costs $0.35.

\[ \text{Cost of Markers} = 100 \times 0.35 = 35.00 \]

Calculate the total cost:

Add the cost of the pens and the cost of the markers:

\[ \text{Total Cost} = 4.50 + 35.00 = 39.50 \]

 

Step 4: Final Answer:

The total cost of 18 pens and 100 markers is $39.50.