Help please

For which pair of functions is (gof)(a)=|a|-2?

The function models the number of accidents per 50 million miles driven as a function

Afactory buys 10% of its components from suppliers b and the rest from supplier c. it is known that 6% of the components it buys are faulty. of the components brought from suppliers a,9% are faulty and of the components bought from suppliers b, 3% are faulty. find the percentage of components bought from supplier c that are faulty.