The number of conifers in the park is 1: 4 deciduous. How many percent of the trees in the park are deciduous?

There are five parts in total 4 + 1 = 5.
The total number of trees is 100%.
For 1 part, 20% falls (100% / 5 = 20%).
Deciduous trees account for 4 parts, then 4 * 20 = 80%.
Answer: 80% of all trees are deciduous.
You can solve this problem using the proportion:
5 – 100%
4 – x%.
Proportion: 5/4 = 100 / x;
5 * x = 4 * 100;
5 * x = 400;
x = 400/5;
x = 80.