Group competition app

General information for the app: App development for group competition
Kind of development: New app from scratch
Description of every page/module: An app that will be played by individuals in a group competition.

Each person will have their own Android Tablet or iPad (not decided hardware yet).

The person is presented with an interface that allows them to adjust three budget calculators up and down, the formulae behind these will be provided to the programmer.

The app should record the persons calculator settings and also their strategy, which they would write in text.

The app should record the persons choices and these need to be displayed on a leaderboard to see which individual is scoring best.
Description of requirements/features: As we don't know what exact hardware this will run on, we are open to suggestions on how it can work. If it needs an online database to operate, please advise too.
Extra notes: This is needed for an event, so we need to find a reliable contractor to undertake the work, there is no possibility for late work. This project will be managed closely every day/week to ensure target is achieved. If the contractor has not made sufficient progress in one week of starting, we will cancel the project.