# Getting a market supply curve from firm supply curve

PFA the image below.

As there are n firms in the market, and a tax of t moves up the cost curves of an individual firm by t units, shouldn't the cost curve of the market move up by n*t units? If yes, why does the book move the curves up only by t units. If no, could you please explain where my reasoning is going wrong?

Thanks

So if there is a tax of $$\t$$ per unit, then the market supply curve will move up by $$\ t$$. (And not by $$\nt$$ as you have suggested.)
Agree with the answer by Kenny, I'd just also add that if you take a look at the horizontal axis, the curve shifts left by $$n(q_1 - q_2)$$ units, while the firm's quantity decreases by $$q_1 - q_2$$. So, in the quantity dimension, you do get that expected factor of $$n$$ when you look at the horizontal difference in the market vs. the firm.