It is 391 because 1+0=1, 9+0=9, and 1+2=3
The formula to find density is Mass/Volume
We have
Density =

Volume =

Hence
Mass = 7.8×10504 = 81931.2 gram
Theos initial balance in his savings account = -$4
Final balance after making a deposit = $25
So, the overall change to his account = $ 29

<h3><em>i </em><em>hope</em><em> it</em><em> helps</em><em> u</em><em> ☠️</em></h3>