Money after w weeks in my account :
[tex]M_m=10w+20[/tex]
Money after w weeks in pet moose account :
[tex]M_p=45w+25[/tex]
Now,
Money I have after 5 weeks, [tex]M_m=10w+20=(10\times 5)+20=\$70[/tex]
Money pet have after 5 weeks, [tex]M_p=(45\times 5)+25=\$250[/tex]
Hence, this is the required solution.