Q1.
Can you tell what percentage of the colour was made using yellow?
Answer
25%.
The mixture is made of red paint and yellow paint only, so the two shares must together make up the whole mixture.
Red = 3/4 of the mixture = 75%
Whole mixture = 1 = 100%
Yellow = 1 – 3/4 = 1/4
1/4 = 1 × 25 / 4 × 25 = 25/100 = 25%
Whole mixture = 1 = 100%
Yellow = 1 – 3/4 = 1/4
1/4 = 1 × 25 / 4 × 25 = 25/100 = 25%
Why it happens: A percentage is a share of one fixed whole. Here the whole is the deep orange paint, and it has only two parts. So the two percentages must add to 100 — you can get the second one either by subtracting the fraction (1 – 3/4) or by subtracting the percentage (100% – 75%). Both give the same answer because 100% is the whole.