16:24 students made at least 80% on the test. The question is what is the ratio of students who scored below an 80% to the total number of students. 8:24 would be the right answer, but since it is asking for the answer in the simplest form, it would be 1:3.
I would say take 2 from eight which equals 6
2x-2yd=y+xd
2x-y=xd+2yd
2x-y=d(x+2y)
(2x-y)/(x+2y)=d
So the answer is <span><span>d=<span><span>2x−y</span><span>x+2y</span></span></span></span>
Answer:
Dave is 18 and his sister is 6.
Step-by-step explanation:
If you do 38 -7x2 you can work out the combined ages of them now which is 24 (you have to do 7x2 because there are two of them and its seven years in the future). Then you can work out their ages using a ratio. Dave’s age : his sister’s age is 3:1 so if you divide 24 by 4 (3+1 = 4 so your can work out one portion of their age) you can find out how old the sister is which is 6. Times that by 3 to get Dave’s age which is 18. A formula for this (where x is his sisters age) would be 3x=38-7x2 which cancels down to 6.
