T remembers his birthday is before 9th July and his wife remembers his birthday is after 7th July.
So the common date is 8th July.
Therefore, T’s birthday is on 8th July.

It is clear that from statement first, we can't find the value of x and n. And with the help of the second statement, we can find the value of x. 
So, from statement first,  x² − 2nx + 81 = 0
Put the value of x=9 form statement second. 
⇒ 9² − 2n × 9 + 81 = 0
⇒ 81 − 2n × 9 + 81 = 0
⇒ n = 9
So, with the help of both statements, we can find the value of n.

In Microsoft Excel, Ctrl+ down arrow key leads to End of column cell movement on spreadsheet.

Conclusions:
I. Some gems are pearls - True
II. Some ornaments are gems - True
Both Conclusion I and II follow.

From I and II, 
White net cloth =L
Remaining = 6 -L
Red = 1/2 × (6 − L) = 3 − L/2
Blue = 3 − L/2
L + 3 − L/2 + 3 − L/2 = 6
Statements I and II together are not sufficient

Acid Rain has pH value of 5.5 or less.
Normal, clean rain has a pH value of between 5.0 and 5.5, which is slightly acidic. However, when rain combines with sulfur dioxide or nitrogen oxides—produced from power plants and automobiles—the rain becomes much more acidic. Typical acid rain has a pH value of 4.0.

Statement (II) is not true, so answer is (B).
On 14 August 2019, Union Jal Shakti Minister Gajendra Singh Shekhawat launched the Swachh Survekshan Grameen 2019, which will be three times bigger in scale than the previous edition of the survey. Around 700 districts and 17,475 villages will be covered under the survey to be conducted in 34 states and union territories. In 2018, around 6,000 villages were covered under it.

Union Minister for Home Affairs, Amit Shah launched the book titled ‘Listening, Learning and Leading’ in Chennai. This book is based on Vice President of India, M. Venkaiah Naidu’s two years in office.

English Actor Steve Coogan will be felicitated with the Charlie Chaplin Award by the British Academy's Los Angeles branch. The 53-year-old actor, whose vast filmography includes movies such as "Around the World in 80 Days", "Philomena", "What Maisie Knew" and "Stan & Ollie", will receive the honour during the 2019 Britannia Awards. The 2019 Britannia Awards will be held on October 25 in Los Angeles (US).