Quiz - Education app

I need educational quiz application for Android and iOS platforms. Also this app should be freemium type, which can be downloaded for free from app store and google play store, but it will have membership purchase options inside of the app. Every membership plan has its own features and advantages. The app will have 4 types of quizzes, 1 quiz with just textual questions, 1 quiz with images, 1 quiz with videos, and 1 custom quiz where user can choose how many textual questions he want, how many images and how many videos, and also he can choose how many minutes he will have to complete it, which will be displayed as countdown. There are many more details which i will explain to the freelancer i choose. But first of all i need to collect informations of the freelancer if everything can be done how i have imagine it, and how i have sketch it. Note: The graphic part of all pages and elements, including the instruction, documentation and detailed explanation will be provided by me, and i will go trough the whole process together with the freelancer. The graphics are done in ( ADOBE ILLUSTRATOR ) So the freelancer needs to have some basic knowledge in this software so he can export everything he needs. Also i want an experienced Android/iOS developer, because this project is going to be long-term project with a lot of updates in future. Before biding attach one of the most complex apps you developed, so i can see your experience.