So, Using your conversion chart(if you have one) you'd see 1 liter makes 1000 milliliters. So, if you have half of a liter(0.5), then you have 500 milliliters. If he adds 300 more, then you get 800 milliliters total, which is also equal to 0.8 liters. Hope this helps!
Do 178 times 28 which equals 4,984 then you do 4,984 decided by 7 which equals 712 because there are 7 days a week. So the answer is 712.