Alibrary expansion begun in 2002, was expected to cost $107 million. by 2006 library officials estimated the cost would be $34 million over budget. by what percent did the actual cost exceed the initial estimate?

This problem is quite easy if you didregard the years. Percent increase is known as
(Final-initial)/(Final)
In this case final would be 107 million +34 million=141 million. Initial would be 107 million.

(142-107)/142=37/142 which is around 26%.