I know this is simple stuff compare to the questions I've seen on this site but please be nice. :) Would be great if anyone could show me how to solve the problem below.
Question:
On a piece of land, 3/8 of the trees are lemon trees. Of the other trees are 8/15 orange trees and 2/5 palm trees. The rest of the trees are mango trees. What's the percent of mango trees? (Answer: 4.2%).
Lemon trees: $\dfrac{3}{8}$
Other trees: $1-\dfrac{3}{8}=\dfrac{5}{8}$
Orange trees: $\dfrac{5}{8}\cdot\dfrac{8}{15}=\dfrac{1}{3}$
Palm trees: $\dfrac{5}{8}\cdot\dfrac{2}{5}=\dfrac{1}{4}$
Mango trees: $1-\left(\dfrac{3}{8}+\dfrac{1}{3}+\dfrac{1}{4}\right)=\dfrac{1}{24}$