we have
Pieces of mail delivered in December by the US postal service
[tex]7.14*10^{10}[/tex]
Pieces of mail delivered in January by the US postal service
[tex]3.21*10^{10}[/tex]
To find the total mail delivered for these two months, sum the two quantities
so
[tex]7.14*10^{10}+3.21*10^{10}=(7.14+3.21)*10^{10}\\=10.35*10^{10} \\=(1.035*10)*10^{10} \\=1.035*(10* 10^{10})\\=1.035*10^{(10+1)} \\= 1.035*10^{11}[/tex]
therefore
the correct solution is [tex]1.035*10^{11}[/tex]
the error is in this part
[tex]10.35*10^{10}[/tex]
To move decimal over one place 10 to the power of 10 should be 10 to the power of 11
[tex]1.035*10^{10}[/tex]
