Final answer:
Doris has 4/5 of her cake left after eating 1/5. She gives Mavis 25% of what's left, equivalent to 1/4 of 4/5, which simplifies to 3/20 of the total cake, making option A (3/20) correct.
Step-by-step explanation:
First, let's identify what portion of the cake Doris has left after eating 1/5 of it. If the entire cake is considered as '1', and Doris ate 1/5, she has 1 - 1/5 left, which simplifies to 4/5 of the cake remaining. Now, Doris gives Mavis 25% of what is left. To find out what fraction of the entire cake this is, we calculate 25% of 4/5. First, convert 25% into a fraction: 25% equals 1/4. Now, multiply 1/4 by 4/5 to find out what portion Mavis gets:
- Multiply the numerators: 1 x 4 = 4
- Multiply the denominators: 4 x 5 = 20
- Combine the multiplication results into a single fraction: 4/20
Simplify the fraction by dividing both the numerator and the denominator by their greatest common divisor, which is 4:
- 4 ÷ 4 = 1
- 20 ÷ 4 = 5
- Thus, the simplified fraction is 1/5
Therefore, the correct answer is 3/20, which makes the answer choice A.3/20 the right one.