Try, please, this: 1) Imagine, that pharmacist used 'x' gr. of 40% solution and 'y' of 70% solution. Together (20 gr. of 52% sol.) it will be x+y=20. 2) From other side, the pharmacist combined 40x and 70y gramms, after obtaining together it is 52(x+y) gramms. In other words 40x+70y=52(x+y) 3) Answer: 8 gr. of 70% solution and 12 gr. of 40%.
I believe it should be 4. Because a trend line should be a line that shows the trend haha so it should be equal. Not sure if that makes sense sorry if I didnt explain it well.
Let's calculate the total cost per year: 6168 + 3280 + 2190 + 1200 = 12,838. Four years will cost 12838 x 4 = 51,352 Your family will help you out with 17,600, so you will need to pay: 51352 - 17600 = 33,752