AD= 7cm

DB = 5cm

AB= AD+DB = 7+5 = 12cm

Since DE is parallel to BC

So, Triangle ADE is similar to triangle ABC

We know,

Area of triangle ADE : Area of triangle ABC = (7/12)² = 49/144

So now, area of quadrilateral BCED = 144-49 = 95

So desired ration = 49: 95

Let outer radius of the cylinder is R cm

According to question,                   

Volume of the hollow cylinder = (22x(R²-7²)x14)/7

2244 = (R²-7²)x44

(R²-7²)x44= 2860

(R²-7²) = 65

R²=65-7²

R²= 65-49

R²= 16

R = 4cm

So the thickness of the cylinder is 4-3 = 1cm

Let efficiencies of A, B and C are 6x, 5x and 7x per day respectively

Efficiency of A, B, and C together = 6x+5x+7x = 18x

Total work done when A, B and C work together = 40*18x units

Required time = 40*18x)/15x =  48 days

Write,

 593 = 423+170

453 = 423+ 30

566= 423+143

503 = 423+ 80

Now expression becomes

(423+170+423+30+423+143+423+80)/423

(Since, 170+30+143+80 = 423)

So,

(423+423+423+423+423)/423 = 5

Hence option A

124/4 = 31, and remainder = 0

So, digit at unit place = 3⁴ = 81

Hence option A

2789941 is completely divisible by 7

So 2789941P can be divisible by 7 is value of P is either 0 or 7

2^x = 2048

2^x = 2x2x2x2x2x2x2x2x2x2x2

2^x =2¹¹

x= 11

so now,

121/11+ 4 = 11+4

=15

Number of boys in class A = 3/7x350 = 150

Number of boys in class B = 2/5x400= 160

Required difference = 160-150 = 10

Total number of students in class C = 220

And total number of students in class A and B = 350+440 = 750

Required percentage = 220x100/750

=30%

According to question,

350+400+220 = 970

Angle for 970 is 360^◦

So angle for 220 is = (360*220)/970 = 81.64^◦