Simplify the following text for a Grade 11 native English-speaking person.
Original: The Firestone Tire and Rubber Company and Bridgestone Tire Company Ltd USA were amalgamated in 1990 and became `` Bridgestone Firestone North American Holdings Ltd '' .
Simplified: The Firestone Tire and Rubber Company and Bridgestone Tire Company Ltd USA were merged in 1990 and became Bridgestone Firestone North American Holdings Ltd. .