8. When Cathy the cat just lazes around, she drinks $60 \mathrm{ml}$ of milk per day. However, each day she chases mice she drinks a third more milk. Also, each day she gets chased by a dog she drinks half as much again as when she chases mice. In the last two weeks Cathy has been chasing mice on alternate days and has also been chased by a dog on two other days. How much milk did she drink in the last two weeks?
A $900 \mathrm{ml}$
B $980 \mathrm{ml}$
C $1040 \mathrm{ml}$
D $1080 \mathrm{ml}$
E $1100 \mathrm{ml}$
Solution
E

On a day Cathy chases mice, the amount of milk she drinks, in $\mathrm{ml}$, is $\left(60+\frac{1}{3} \times 60\right)=$ 80. On a day when she gets chased by a dog, the amount of milk she drinks, in ml, is $\left(80+\frac{1}{2} \times 80\right)=120$. Therefore, in the last two weeks, the amount of milk Cathy has drunk, in $\mathrm{ml}$, is $(7 \times 80+2 \times 120+5 \times 60)=1100$.