Answer:
7x - 5y = -5 this is the standard form
First we'll substitute 
with 
Then we can separate this.
Then we'll solve this.
Then we'll plug in to find the extraneous solutions (if any)
Remark
The way you have to set this up is to take the new number for the males and put it over the total for the males and females. The new number for the males / total = 3/5.
Step One
Find the total number of females
100 + 160 = 260 when 100 females have been added to the study.
Step Two
Find the number of males
The total number of males = 240 + x where x is the number of males to be added.
Step Three
Find the total for both
260 + 240 + x = Total
500 + x = Total.
Step Four
Find the ratio of males to total
(240 + x) / (500 + x) = 3/5
Step Five
Cross multiply and solve
(240 + x)*5 = (500+x)*3
1200 + 5x = 1500 + 3x Subtract 1200 from both sides.
5x = 1500 - 1200 + 3x
5x = 300 + 3x Subtract 3x from both sides.
5x - 3x = 300
2x = 300 Divide by 2
x = 300 / 2
x = 150
Check
(240 + 150 ) / (500 + 150) = ? 3/5
390 / 650 = ? 3/5
39/65 = ? 3/5 Divide the top and bottom on the left by 13
3/5 = 3/5 and it checks.
Answer 10x
so the question doesn’t state the number of pages in these 10 books so i guess the answer would be 10x not a lot of info is given
