Exercise 1: Trace an Image File Size Calculation
Problem
Calculate the file size of a 1280 × 720 pixel image with 24-bit colour.
Express the final answer in megabytes (MB).
Complete each step:
Formula: Width × Height
1280 × 720 = ?
Formula: Total pixels × Colour depth
921,600 × 24 = ?
Formula: Bits ÷ 8
22,118,400 ÷ 8 = ?
Formula: Bytes ÷ 1,000,000
2,764,800 ÷ 1,000,000 = ?
Exercise 2: Trace an Audio File Size Calculation
Problem
Calculate the file size of a 2-minute stereo audio recording with:
- Sample rate: 44,100 Hz
- Bit depth: 16 bits
Express the final answer in megabytes (MB).
Complete each step:
2 minutes = ? seconds
Formula: Sample rate × Duration × Bit depth
44,100 × 120 × 16 = ?
Stereo = mono × 2 channels
84,672,000 × 2 = ?
169,344,000 ÷ 8 = ?
21,168,000 ÷ 1,000,000 = ?
Exercise 3: Unit Conversion Chain
Problem
Convert 5 GB through all the smaller units down to bits.
Complete the conversion chain:
5 GB × 1,000 = ? MB
5,000 MB × 1,000 = ? KB
5,000,000 KB × 1,000 = ? bytes
5,000,000,000 bytes × 8 = ? bits
Exercise 4: Work Backwards
Problem
An image file is 3.6 MB. If the image has 24-bit colour and is 1500 pixels wide, how many pixels tall is it?
Work backwards through the formula:
3.6 MB × 1,000,000 = ? bytes
3,600,000 bytes × 8 = ? bits
Total bits ÷ Colour depth = Total pixels
28,800,000 ÷ 24 = ? pixels
Total pixels ÷ Width = Height
1,200,000 ÷ 1,500 = ? pixels