Quantitative Aptitude - Arithmetic Ability Questions

For what value of k, the expression x6– 18x3 + k will be a perfect square?

If tan 45° + cosec 30° = x, then find the value of x.

If A = 1 – 10 + 3 – 12 + 5 – 14 + 7 + ... upto 60 terms, then what is the value of A?

Three bottles of equal capacity have mixture of milk and water in ratio 5 : 7, 7 : 9 and 2 : 1 respectively. These three bottles are emptied into a large bottle. What is the percentage of milk in the new mixture?

A can do a work in 21 days and B in 42 days. If they work on it together for 7 days, then what fraction of work is left?

Cost price of a calculator is Rs 495. If the profit percentage is 40%, then what is the value (in Rs) of profit?

Two numbers whose sum is 84 can not be in the ratio

A boy found the answer for the question "Subtract the sum of 1/4 and 1/5 from unity and express the answer in decimals" as 0.45. The percentage of error in his answer was