Is or are?

[Jamgirl]

I am in a pickle about this. Do we say:

'Your knowledge and experience is invaluable'
or
'Your knowledge and experience are invaluable'.

To my ear, 'is' sounds better. Logically though, should it be 'are' because there are two things in the sentence?

If it is 'is', can someone explain why?

Thanks

[5jj]

'Your knowledge and experience is invaluable'
or
'Your knowledge and experience are invaluable'.

Only 'are' is correct.

I think it is possible that some speakers, with a mental picture of 'combination of knowledge and experience' might use 'is', and I also feel that many listeners would not notice anything unusual.

It seems unacceptable to me in writing.

[Jamgirl]

Only 'are' is correct.

I think it is possible that some speakers, with a mental picture of 'combination of knowledge and experience' might use 'is', and I also feel that many listeners would not notice anything unusual.

It seems unacceptable to me in writing.

Thank you for that. I knew logically it had to be 'are' and many arguments here took place about whether you could group the 2 things (knowledge and experience) together to consider it as 1 thing, and use 'is'. I'll have to let my colleagues know that it is 'are'.