<span>x-y=2y -> x=3y and
3x-40+2y=180 --> 9y-40+2y=180 --> 11y=220 --> y=20, x=60 --> <A=<C=140 degrees, <B=<D=40 degrees.</span>
Divide total cups he drank by the # of cups in each bottle.
7 ÷ 3= 2.3333
Since each bottle only holds 3 cups, he drank 3 bottles of water. He didn't drink all the water in the third bottle, but he started drinking the third bottle.
ANSWER: 3 bottles
Hope this helps! :)