Given,
CP of cosmetics = Rs 360 per dozen
SP of a pair of cosmetics = Rs 80
To find,
The gain percent
Solution,
1 dozen = 12 items
CP of 1 cosmetic = 360/12 = Rs 30
SP of 1 cosmetic = 80/2 = Rs 40
Profit = SP-CP
= Rs 40 - Rs 30
= Rs 10
Profit percentage is given by :

So, the profit percentage is 33.34%.
This is the concept of algebra, to get the slope of the line we need to rewrite the equation in slope intercept form y=mx+c, where m=slope, c=y-intercept.
Therefore re-writing our expression in slope-intercept form we get:
7x-3y=10
-3y=-7x+10
y=7/3x-10/3
The slope=7/3
hence we conclude that the slope of the line perpendicular to this is -3/7
Answer: -25
Step-by-step explanation:
First, this shoudnt be in mathematics and second, i think this is socila studies.