Quantitative Aptitude - Arithmetic Ability Questions

In the following question, select the odd number pair from the given alternatives.

A box of 20 items was bought for Rs. 6,400 after a discount of 20%. Find the cost of each item.

If cos 135° = x, then the value of x is

The marked price of an article is Rs 1200 and retailer gets a discount of 25%. If he sells that article for Rs 1200, then what is the profit percentage of retailer?

Among four students sitting in a row, average age of last three students is 20 years and the average age of first three students is 21 years. If the age of first student is 26 years, then what is the age (in years) of the last student?

A factory buys 10 machines. 2 Machine­A, 3 Machine­B and rest Machine­C. Prices of the machines are Rs 95000, Rs 60000 and Rs 50000 respectively. What is the average cost of these machines?

A certain number of men agreed to do a work in 20 days. 5 men did not come for work. Others completed the work in 40 days. Find the number of men who had agreed to do the work originally.

What is the largest 4 digit number which is exactly divisible by 81?