Answer :
[tex]7.5lbs[/tex]
1) Note that Mike bought 12 1/2 lbs and the dogs ate 3/5 of those 12 1/2 lbs. So let's first rewrite that mixed number into an improper fraction for convenience:
[tex]12\frac{1}{2}=\frac{2\times12+1}{2}=\frac{25}{2}[/tex]Note that we kept the denominator.
2) So now, let's calculate how much food did the dogs eat by multiplying
3/5 by this 25/2
[tex]\frac{3}{5}\times\frac{25}{2}=\frac{75}{10}=\frac{15}{2}=7.5lbs[/tex]Note that we simplified that fraction to get an irreducible number