When is 'International Senior Citizen Day' celebrated every year?

If $${4x^2={15^2-9^2}}$$ then the value of x is

A man spends Rs. 1800 monthly on an average for the first four months and Rs. 2000 monthly for the next eight months and saves Rs. 5600 a year. His average monthly income is

Find the average of all prime numbers between 30 and 50.

In a factory men, women and children were employed in the ratio 8:5:1 to finish a job and their individual wages were in the ratio 5:2:3. Total daily wages of all amount to Rs. 318. Find the total daily wages paid to each category.

What is a difference between simple interest and compound interest in 1 year at a rate of 10 percent on an amount of Rs. 1200. If interest is half yearly compounded?

A drug dealer sells a tablet for 5 rupees. If he buys a tablet packet for Rs 50 and if a tablet packet contains 25 tablets, what will be his profit percentage?

Rahul can do a work in 20 days. Rahul and Shyam together do the same work in 15 days. If they are paid Rs. 400 for that then what is the share of each.