Quantitative Aptitude - Arithmetic Ability Questions

The mean of 100 observations was calculated as 40. It was found later on that one of the observations was misread as 83 instead of 53. The correct mean is:

A sum fetched a total simple interest of Rs 1200 at the rate of 7.5%/yr in 4 years. What is the sum (in Rs)?

The average cost of 4 items in a shopping list is Rs 1,250. If one more item whose cost is Rs 2,000 is added to the list what will be the new average (in
Rs)?

If x + y = 12 and x2 + y2 = 94, then xy is 

Sum of two numbers is thrice their difference. Their ratio is

If 7x - [3(2x - 3)]/2 = 1/2, then what is the value of x?

The marked price of an article is Rs 2400. It is sold at two successive discounts of 10% and 15%. What is the selling price (in Rs) of the article?

Select the odd letters from the given alternatives.