Suppose you have eight 'black and white' images taken with a 1‐megapixel…
2021
Suppose you have eight 'black and white' images taken with a 1‐megapixel camera and one '8‐color' image taken by an 8‐megapixel camera. How much hard disk space in total do you need to store these images on your computer?
- A.
1 GB
- B.
4 MB
- C.
3 MB
- D.
3 GB
Attempted by 106 students.
Show answer & explanation
Correct answer: B
Key idea: compute bits per pixel, convert to bytes, then to megabytes, and sum all images.
Black-and-white images: assume 1 bit per pixel (black or white). Each 1-megapixel image has 1,000,000 pixels → 1,000,000 bits = 125,000 bytes ≈ 0.125 MB. Eight such images total 8 × 0.125 MB = 1 MB.
8-color image: 8 colors require 3 bits per pixel (since 2^3 = 8). An 8-megapixel image has 8,000,000 pixels → 8,000,000 × 3 bits = 24,000,000 bits = 3,000,000 bytes = 3 MB.
Total storage required: 1 MB (all black-and-white images) + 3 MB (the 8-color image) = 4 MB.
Note: this assumes uncompressed storage and uses decimal megabytes (1 MB = 1,000,000 bytes).