Question about after than

hi, I'm a student from China. Since no one can help me here, I hope this forum can.

a) Older women showed much greater increases in speed than (was) expected.

Is "was" optional above?

Although I didn't read many English books, I did see 'than was expected' and 'than expected' before.

I really want to thank you if you can help.

Is this sentence OK?

b) He should really carry more loose change.