Answer: 24% of the books read are magazine
Step-by-step explanation:sum of the books read is 20+12+18=50 books.
Therefore 12 of the books are magazine.
Then, 12 of 50 =24%( 12÷50)× 100/1 = 24%
We do like the following:
Set the first number is a and the second is b.
We have two equations: a+2xb=24, 2xa+b=21
And we have 2xa+4xb=48 or 2xa=48-4xb
So: 48-4xb+b=21 or -3xb=21-48=-27 and we got b=-27:(-3)=9 and a= 6
a=6 and b=9
42,600 - 25,800 = 16800. That is the increase in 15 years.
You then calculate the increase as a percentage of the original population; 25,800.
16,800 / 25,800 * 100 = 65.11%
B hope it helps SORRY IF IM WRONG