The printer in the maths building charges 10p to print one black and white page and 15p to print one colour page.

Mrs. Henderson pays £5.50 to print some documents. The ratio of black and white pages to colour pages that she prints is 4:1.

How many pages does she print?

Show your calculations and/or workings out here:



Answer :

Certainly! Let's solve this problem step-by-step:

1. Identify the costs and ratio:
- The cost to print one black and white page is £0.10 (10p).
- The cost to print one color page is £0.15 (15p).
- The ratio of black and white pages to color pages is 4:1.

2. Express the quantities in terms of a single variable:
- Let the number of color pages be [tex]\( x \)[/tex].
- Since the ratio of black and white pages to color pages is 4:1, the number of black and white pages will be [tex]\( 4x \)[/tex].

3. Set up the equation for the total cost:
- The total cost to print all pages is £5.50.
- The cost to print [tex]\( 4x \)[/tex] black and white pages is [tex]\( 4x \times 0.10 \)[/tex] pounds.
- The cost to print [tex]\( x \)[/tex] color pages is [tex]\( x \times 0.15 \)[/tex] pounds.
- The total cost equation will be:
[tex]\[ 4x \times 0.10 + x \times 0.15 = 5.50 \][/tex]

4. Simplify and solve the equation:
- Simplify the left side of the equation:
[tex]\[ 0.40x + 0.15x = 5.50 \][/tex]
- Combine the terms:
[tex]\[ 0.55x = 5.50 \][/tex]
- Solve for [tex]\( x \)[/tex]:
[tex]\[ x = \frac{5.50}{0.55} = 10 \][/tex]
Therefore, [tex]\( x = 10 \)[/tex]. This means there are 10 color pages.

5. Calculate the number of black and white pages:
- Since the number of black and white pages is [tex]\( 4x \)[/tex]:
[tex]\[ 4x = 4 \times 10 = 40 \][/tex]
Therefore, there are 40 black and white pages.

6. Calculate the total number of pages printed:
- Total pages = black and white pages + color pages:
[tex]\[ 40 + 10 = 50 \][/tex]

So, Mrs. Henderson prints 50 pages in total: 40 black and white pages and 10 color pages.