If the total production of cars during a certain period was 42000, how many more blue cars were sold in comparison to golden cars.

In 2008, number of students in Arts = Total Student x 12%
In 2008, number of students in Arts = 35000x12 /100 = 4200
In 2009, number of students in Arts = Total Student x 11%
In 2009, number of students in Arts = 40000x11/100 = 4400
In 2008, number of students in Agriculture = Total Student x 7%
In 2008, number of students in Agriculture = 35000 x 7/100 = 2450
In 2009, number of students in Agriculture = Total Student x 5%
In 2009, number of students in Agriculture = 40000x5/100 = 2000
In 2008, number of students in Pharmacy = Total Student x 6%
In 2008, number of students in Pharmacy = 35000 x 6/100 = 2100
In 2009, number of students in Pharmacy = Total Student x 9%
In 2009, number of students in pharmacy = 9/100 x 40000 = 3600
Hence, in Agriculture there was decrease in the number of students from 2008 to 2009.

In 2008, the number of students studying Pharmacy = 35000 x 6/100 = 2100
In 2009, the number of students studying Pharmacy = 9 x 40000 /100 x = 3600
Hence, their ratio = 2100 : 3600 = 7 : 12

In 2008, the number of students studying Arts and commerce together
= (12 + 22)/100 x 35000 = 34 x 350 = 11900
In 2009, the number of students studying Arts and Commerce together
= (11 + 24)/100 x 40000 = 35 x 400 = 14000
Hence, required percentage = 11900/14000 x 100 = 85%

In 2008, number of students in Science = Total Student in 2008 x 24%
In 2008, number of students in Science = 35000 x 24% = 35000 x 24/100 = 8400
In 2009, number of students in Science = Total Student in 2009 x 22%
In 2009, number of students in Science = 40000 x 22% = 40000 x 22/100 = 8800
Increase in number of students of Science = 8800 - 8400 = 400
Hence, Increase percentage = 400 x 100 /8400 = 400/84 = 4.7%
Similary
Increase in number of students of Commerce = 24x40000/100 - 22x35000/100 = 9600 - 7700 = 1900
Hence, their increase percentage = 1900x100 /7700 = 1900/77 = 24.67%
Increase in number of student of Arts = 11/100 x 40000 - 12/100 x 35000 = 4400 - 4200 = 200
Hence , their increase percentage = 200/4200 x 100 = 4.67
Increase in number of student of Medicine = 10/100 x 40000 - 11/100 x 35000 = 4000 - 3850 = 150
Hence, their increase percentage = 150/3850 x 100 = 3.89%
So, in Medicine the percentage increase in the number of student was minimum from 2008 to 2009

In 2008, number of students in Engineering = Total Student x 18%
In 2008, the number of students in Engineering = 35000x18/100 = 6300
In 2009, number of students in Engineering = Total Student x 19%
In 2009, the number of student in Engineering =40000 x19/100 = 7600
Required percentage = (number of students in Engineering in 2009 - number of students in Engineering 2008) x 100 / number of students in Engineering in 2008
Required percentage = (7600 - 3600)x 100 /6300 = 1300/63 = 20.6 ? 20%

Let us assume the car which is 40% more popular than black is a and total number of car is P.
According to question,
(P x a/100 ) - (P x 5/100) = P x 5/100 x 40/100
P(a - 5)x1/100 = P x 5/100 x 40/100
(a - 5) = 5 x 40/100
(a - 5) = 200/100 = 2
a - 5 = 2
a = 2 + 5 = 7
40% more popular than Black cars = 7% popular Silver cars.

The percentage of White, Black and Red Cars = 25 + 20 + 5 = 50%

If 3% increase in the production of Blue cars, then percentage of Blue cars = 12 + 3
Hence, percentage of (Blue + Red) cars = 15 + 20 = 35

Required percentage = number of students enrolled in Cooking classes x 100/ number of students enrolled in Dance classes
Required percentage = 22 x 100/21 = 104.76

Number of students enrolled in Painting classes = % of students enrolled in Painting classes x 100/ Number of total students
Number of students enrolled in Painting classes = 3600 x 15/10 = 540