I'll give you that a man and a woman of the same physical size can each generally perform the same physical tasks. I'll also agree they should be paid the same.
However, saying the average sized woman can perform the same physical tasks as the average sized man is easily shown to be false using simple physics.
This is the wrong way to go about things; I'm a very strong beleiver in the principle of equality, that is, the equality in all social dealings of men and women, between races, abled and disabled, those of different nationalities, of different professions etc. But it must be stressed that asserting people have the same capabilities isn't the right way to go about it. Your principle will fail the second that we get to some imbalance which can't be whisked away as you're doing now - for example, you wouldn't make the same claim about someone with Down's syndrome being compared to someone without.
Your failing is that you predicate the idea of equality on utilitarian grounds, that is to say, you believe people should be treated equally, and so you try to justify this by saying they're actually the same in mental and physical tasks. This doesn't work, and it can't be generalised. There are differences, but we should be saying: those differences shouldn't matter to the worth of a person (if we really must go about considering people in the economic sense of having value, which I think is a concept worth repudiating).
The claim you're making seems much more like a strawman, so I'd be inclined to say you're trolling; a strawman very similar to yours was made by Tugan more than 100 years ago, and quickly put down by V.I. Lenin[0]:
>It goes without saying that in this respect men are not equal. No sensible person and no socialist forgets this. But this kind of equality has nothing whatever to do with socialism. If Mr. Tugan is quite unable to think, he is at least able to read; were lie to Lake the well-known work of one of the founders of scientific socialism, Frederick Engels, directed against Dühring, he would find there a special section explaining the absurdity of imagining that economic equality means anything else than the abolition of classes.
> we're built differently both mentally and physically
You're incredibly sexist. You undoubtedly are part of the reason women are paid 60% what men are. I hope you are fired from wherever you work as you're part of the problem.
This is not Reddit. You first need to show evidence that women are paid 60% of what men are paid for the same jobs. Once you can’t (because the evidence says the opposite) you then need to show evidence that women choose jobs and make career choices different from men because of cultural reasons. Once you can’t do that either because the evidence shows the opposite then you’ll need to adjust your beliefs in light of the evidence like a proper reasonable person. After which you can stop telling all women their decisions to live life differently from men makes them inferior to men. It’s both hateful to men and women when you do that.