Let present Anirudh's age be 'A' and Bhavana's age be 'B'

Given seven years, their ratio is 7:9

=> A-7 : B-7 = 7 : 9

=> 9A - 7B = 14 .......(1)

And given,

Chandhu is 12 years older than A nad 12 years younger than B

=> C = A + 12....(2)

=> B = C + 12

=> B = A + 12 + 12 .....(From (2))

=> B = A + 24 ....(3)

Put (3) in (1)

9A - 7(A+24) = 14

9A - 7A - 168 = 14

2A = 182

=> A = 91 years

=> C = A + 12 = 91 +12 = 103 years.

Total number of students in the class = 28 + 6 i.e, from top(7-1)

28 + 6 = 34  

Let the present ages of A and B be 'x' and 'y' respectively

From the given data, 

[(x-2) + (y-2)]/2 = 26

=> x+y = 56

But given the age of A, 5 years hence is 40 yrs => present age of A = 40 - 5 = 35 yrs

=> x = 35 => y = 56 - 35 = 21

=> Age of B = 21 yrs

Given B is 5 years younger to C,

=> Age of C = 21 + 5 = 26 yrs

=> Required Difference between ages of A and C = 35 - 26 = 9 yrs.

Let the speed of the boat upstream be p kmph and that of downstream be q kmph

Time for upstream = 8 hrs 48 min = 845hrs

Time for downstream = 4 hrs

Distance in both the cases is same.

=> p x  845= q x 4

=> 44p/5 = 4q

=> q = 11p/5

 Now, the required ratio of Speed of boat : Speed of water current

= q+p2:q-p2

=> (11p/5 + p)/2  : (11p/5 - p)/2

=> 8 : 3

Energy tranfer takes place either by means of Heat or Work only in Thermodynamics.

Heat :: Heat Energy is defined as Energy that can be transferred due to temperature change.

Whereas

Thermal Energy :: Thermal Energy is the Internal Energy stored in the system maintained at a certain Temperature.

Let the number of boys = x

From the given data,

=> [21x + 16(18)]/(x+16) = 19

=> 21x - 19x = 19(16) - 16(18)

=> 2x = 16

=> x = 8

Therefore, the number of boys in the class = 8.

Article-22 :: Protection against arrest and detention.

No person who is arrested shall be detained in custody without being informed of the grounds for such arrest nor shall he be denied the right to consult and to be defended by a legal Practioner of his choice.

Sum of ages of husband, wife and child= (24 × 3) + 9 = 81 years

Sum of ages of wife and child => 25 × 2 + 10 = 50 + 10 = 60 years

Age of husband = 81 - 60 = 21 years.