The price of coffee is increased by 15% and a house wife reduced her consumption of coffee by 15% and hence her expenditure on coffee?

Let length of a rectangle = 100 m,
Breadth = 100 m
New length = 160 m,
New breadth = B meters
Then, 160 x B = 100 x 100
? B = (100 x 100) / 160 = 125/2
Decrease in breadth = (100 - 125/2)% = 37¹/₂%

Let length of square = 100 m and breadth of square = 100 m
Area = (100 x 100) m² = 10000 m²
New length = 130 m and breadth = 120 m

New area of rectangle = (130 x 120) m² = 15600 m²
Increase % = (5600 / 10000) x 100 % = 56%

Let radius of circle = 100 m
New radius = 101 m
original area = [? x (100)² ]m²
New area = [? x (101)² ]m²
Increase% = [? x {(101)² - (100)²} / { ? x (100)²} ] x 100 %
= 201 / 100% = 2.01%

Let side of square = 100 cm
Area = (100 x 100)cm² = 10000 cm²
New area = (130 x 130)cm² = 16900 cm²
Increase in area = (6900 / 10000) x 100% = 69%

Let the total number of students be 100
Then, n(A ? B) = n(A) + n(B) - n(A ? B) = (72 + 44 - 100)% = 16%
Now,16% of N = 40
? (16 x N) / 100 = 40
? N = (100 x 40) / 16 = 250

Required number = 800 x (1 + 15/100)²
= 800 x (23/20) x (23/20)
= 1058

Let original rate = Rs. P per kg
New rate = 79% of Rs. P per kg
= Rs. (79 x P)/100) per kg
? {(100/79P)/100} - {100/P} = 10.5
? 10000/79P - 100/P = 10.5
? 10000 - 7900 = 10.5 x 79P
? P = 2100/(10.5 x 79)
? P = 2100/(10.5 x 79)
Reduced rate = Rs. (79/100) x 2100/(10.5 x 79) per kg = Rs. 2 per kg.

Surface area sphere = 4? x (10)²
volume sphere=4?/3 x (10)³
= (4000?/3) cm³

? Required percentage = {(400? x 3) / (4000?)} x 100 %
= 30%

? 5% of A=15% of B and 10% of B = 20% of C
? A/20 = 3B/20 and B/10 = C/5
? B = 2C
? A/20 = (3/20) x 2C = 3C/10 =(3/10) x 2000 = 600
? A = (600 x 20) = 12000,
B = (2 x 2000) = 4000
? A + B + C = (12000 + 4000 + 2000) = 18000

Total population = 300000
Total number of males = 180000
Total Literates = 50% of total population = 150000
Number of literate males = 70% of males = 126000
? Number of literate females = 150000 - 126000 = 24000