Why is $2\cdot e^{3}$ equal to $40 \cdot 2$ in this integration question?

Question

I'm trying to understand an integration question:

$I = \int 2\cdot e^{x}$, given that $I = 50 \cdot 2$ when $x = 3$

I understand the integration, which is:

$I = \int 2\cdot e^{x} = 2e^{x} + C$

However, the next statement is losing me:

$\therefore 50 \cdot 2 = 2e^{3} + c = 40 \cdot 2 + c$

My calculator is showing $e^{3}$ to be $20.085$ so I'm not clear why $2e^{3}$ is printed in the question as $40 \cdot 2$

Simple explanations will be preferred over more complex explanations.

Answer 1

It would appear that the dots in $50\cdot2$ and $40\cdot2$ are to be interpreted not as multiplication but as decimal points. $2e^3$ is (to one decimal place) $40.2$.

Answer 2

You need to check well that that is not $$40.2$$ instead of $$40\cdot2.$$ If you're sure after checking that it's the latter, then the only reasonable explanation is that it's a typo.

Also, it's not true that $$2\times e^3=40.2,$$ but I understand if the book is an engineering or physics book. ☺