Maria + 12 = 2 × (Steven + 12)
Maria + Steven = 36
Maria = 36 - Steven
36 - Steven + 12 = 2 × (Steven + 12)
48 - Steven = 2 × Steven + 24
48 = 3 × Steven + 24
3 × Steven = 48 - 24 = 24
Steven = 8

 Let the ages of Abhay and his father 10 years ago be x and 5x years respectively. Then,

Abhay’s age after 6 years = (x + 10) + 6 = (x + 16) years

Father’s age after 6 years = (5x + 10) + 6 = (5x + 16) years.

(x + 16) =  (5x+16) ⇔ 7 (x + 16) = 3 (5x + 16) ⇔ 7x + 112 = 15x +48

⇔ 8x = 64 ⇔ x = 8

Hence, Abhav's father's present age = (5x + 10) = 50 years.

simple logic ---

We know that 20 student’s average = 20 years

20 people total age = 20 × 20 = 400 years

Including Teacher’s

21 people average = 22 years

21 people total age = 21 × 22 = 462

We know the age of 20 students = 400 years

We know the age of 21 people (20 students + Teacher) = 462

So the age of Teacher will be 462 – 400 = 62 Years.

Let the school ages of Nikita and Sonam be 5x and 6x years respectively. Then,

⇔ 15 = 15.

Thus, sonam's age cannot be determined

Cindy + 9 = 57
Cindy = 57 - 9 = 48
(Cindy + 13) + (Miguel + 13) = 126
(48 + 13) + (Miguel + 13) = 126
Miguel + 74 = 126
Miguel = 126 - 74 = 52

Let the son’s present age be x years. Then, man’s present age = (x + 24) years.

(x + 24) + 2  = 2(x + 2)

x + 26 = 2x + 4

x = 22.

Jennifer + 6 = 50
Jennifer = 50 - 6 = 44
(Jennifer + 5) + (Maria + 5) = 96
(44 + 5) + (Maria + 5) = 96
Maria + 54 = 96
Maria = 96 - 54 = 42

Let Gaurav’s and Sachin’s ages one year ago be 6x and 7x years respectively. Then Gaurav’s age 4 years

Hence = (6x + 1) + 4 = (6x + 5) years

⇔8 (6x + 5) = 7 (7x + 5) ⇔ 48x + 40 = 49x + 35 ⇔ x = 5.

Hence, sachin's present age = (7x+1) = 36 years.

Simple logic……

Amar is as much younger than Raja as he is older than Kiran. Try to understand this sentence. According to this sentence you can understand that

Amar is younger than Raja that means there is some X years difference between Amar and Raja.

Amar is older than Kiran with same age difference (X years) between Amar and Kiran.

But we know that the ages of Amar and Raja are 30 and 36 years.

So the difference between their ages is = 6 years

So the difference between Amar and Kiran should be = 6 years.

We know the age of Amar as 30 years and Kiran is younger than Amar for 6 years. So he should be of 24 years.

With a single glance you can calculate answer for these type of problems.

Let their present ages be 4x, 7x and 9x years respectively.

Then, (4x – 8) + (7x – 8) + (9x – 8) = 56 ⇔ 20x = 80 ⇔ x = 4

∴ Their present ages are 16 yers, 28 years and 36 years respectively.