Ravi's brother is 3 yr elder to him. His father was 28 yr of age when his sister was born, while his mother was 26 yr of age when he was born. If his sister was 4 yr of age when his brother was born, the ages of Ravi's father and mother respectively when his brother was born were?

Let ages of man and his son are 8k yr and k yr, respectively .
According to the question,
(8k + k)/2 = 27
? k = (27 x 2)/9 = 6
Hence, age of son after 6 yr = 6 + 6 = 12 yr

Let Arnav's age = k yr
Then, Palash's age = 3k yr
Acoording to the question, 3k + 7 = 2(k + 7)
? 3k + 7 = 2k + 14
? k = 7

? Age of Arnav after 14 yr = 7 + 14 = 21 yr
and Palash's present age = 21 yr

Hence, Palash's age is one time of Arnav's age .

4 yr ago, let Ram's age = k yr and Shyam's age = 3k/4 yr
Now, Ram's present age = (k + 4) yr
and Shyam's present age = (3k/4 + 4) yr
According to the question, 5/6(k + 4 + 4) = (3k/4 + 4 + 4)
? 4 (5k + 40) = 6(3k + 32)
? 20k + 160 = 18k + 192
? 2k = 32
? k = 16
Hence, present age of Shyam = (3/4) x 16 + 4 = 16 yr

? Total age of five members of a family = 24 x 5 = 120
? Total age of four members at the time of birth of youngest = 120 - 8 x 5
= 120 - 40 = 80 yr
Hence, required average age = 80/4 = 20 yr

Let the present ages of Manoj and Wasim are 3k yr and 11k yr, respectively.
According to the question ,
11k = 85 - 7 - 12
? 11k = 66
? k = 6
? Present age of Manoj = 3 x 6 = 18 yr
Hence, present age of Manoj's father = 18 + 25 = 43 yr

Let us assume the present ages of Mohan and Sohan be 3x years and 4x years; then,
4 Four years ago the ages was 3x - 4 and 4x - 4 years.
According to question, 4 Four years ago the ratio was 5 : 7
( 3x - 4 ) / ( 4x - 4 ) = 5/7
? ( 3x - 4 ) 7 = 5 ( 4x - 4 )
? 21x - 28 = 20x - 20
? 21x - 20x = 28 - 20
? x = 8
Hence, their present ages, 3x = 3 x 8 = 24 years; 4x = 4 x 8 = 32 years.
So their present ages 24 and 32 years.

For two years having same calendar must have two common conditions: both having same length in terms of number of days and first day of the week.

The year 1991 has 365 days,,that is 1 odd day , year 1992 has 366 days , i.e. 2 odd days , year 1993 has 365 days i.e. 1 odd day. the years 1994,1995,1996 have 1 odd day each.

the sum of odd days so calculated from year 1990 to 1996 .
(1+2+1+1+1+1)=7 odd days. 5

hence, the year 1997 will have same calendar as that of year 1990.

Each day of the week is repeated after 7 days
? After 63 days, it would be Friday
So, After 62 days, it would be Thursday

The year 1984 being a leap year, it has 2 odd days. So, the day on 2nd July, 1985 is two days beyond the day on 2nd July, 1984. But, 2nd July 1985 was Wednesday.

? 2nd July, 1984 was Monday

No of days = Jan. + Feb. + March
30 + 28 + 15 = 73 days