Initial speed = 80km/hr
Total distance = 80 x 10 = 800km
New speed = 800/4 =200km/hr
Increase in speed = 200 - 80 = 120km/hr

The main differenc between View and Materialized View states that -

1. View means it stores the SQL statement in the database and let you use it as a table. Everytime you access the view, the SQL statement executes.

2. Materialized view means it stores the results of the SQL in table form in the database. SQL statement only executes once and after that everytime you run the query, the stored result set is used. Advantage include quick query results.

We need to find the total cost to send r messsages, r > 1000.

The first 1000 messsages will cost Rs.p each (Or) 

The total cost of first 1000 messsages = Rs.1000p

The remaining (r - 1000) messsages will cost Rs.q each (Or)

The cost of the (r - 1000) = Rs.(r - 1000)y

Therefore, total cost = 1000p + rq - 1000q

= 1000(p - q) + qr

The following arrangements satisfy all 3 conditions.

Arrangement 1: 3 books in a row; 12 rows.

Arrangement 2: 4 books in a row; 9 rows.
Arrangement 3: 6 books in a row; 6 rows.
Arrangement 4: 9 books in a row; 4 rows.
Arrangement 5: 12 books in a row; 3 rows.

Therefore, the possible arrangements are 5.

Let the salary of Karthik 2 years ago be Rs.100
So, Lucky's salary 2 years ago was Rs.50

Karthik's present salary has seen two 10 percent increases. So as Lucky's salary.

So, Karthik's salary 1 year ago = 100 + 10% of 100 = 100 + 10 = 110.
Karthik's present salary = 110 + 10% of 110 = 110 + 11 = 121.

Lucky's salary 1 year ago = 50 + 10% of 50 = 50 + 5 = 55
Lucky's present salary = 55 + 10% of 55 = 55 + 5.5 = 60.5

Lucky's present salary of 60.5 = 50% of Karthik's present salary of 121.

The Teesta River is a 309 km long river flowing through the Indian states of West Bengal and Sikkim, before going to Bay of Bengal through Bangladesh.

Manju borrows Rs. 5000 for 2 years at 4% p.a. simple interest 

She also lends it at 6 1⁄4% p.a for 2 years 

=> Total Gain = 6 1/4% − 4% = 2 1/4%

So her gain in the transaction for 1 year

= The simple interest she gets for Rs.5000 for 1 year at 2 1⁄4% per annum

= PTR100=5000×94×1100 = Rs. 112.5/ year.

Let the two digits be x & y

From given data in the question, we get

x + y = 3(x - y)

x + y = 3x - 3y

=> 2x = 4y

x/y = 2/1

For having the 2:1, numbers satisfying are

12, 21, 24, 42, 36, 63, 48, 84

From this 36 is eleminated because it is a perfect square and no others are prime or perfect squares.

Hence, there exists 7 such 2-digit numbers => 12, 21, 24, 42, 63, 48, 84.