Answer:
If a country has a low literacy rate it means education is worse (obviously), so worse the education means less educated people, which means less architects, to build good roads, buildings, ect. Also less scientist to increase crop efficiency, and of course less people educated in business so basically it effects the economy a lot when there is a low literacy rate.
And inversely if there is more educated people (higher literacy rate) there is more of all of the above.