Quantitative Aptitude - Arithmetic Ability Questions

The mean of 20 observations is 19. One more observation is included and the new mean becomes 20. The 21st observation is

What is the simplified value of 1-sin A1+sin A ?

What will be the net discount percentage of three successive discounts of 20%, 10% and 30%?

The ratio of incomes of P and Q is 5 : 3. Ratio of income of Q and R is 5 : 2. If one-fourth of P’s income is Rs 500 more than the R’s income, then what is the income (in Rs) of Q?

What is the reflection of the point (-0.5, 6) in the x-axis?

Find the unit place digit in 71 x 72 x 73 x 74 x 76 x 77 x 78 x 79.

There are three bottles of mixture of syrup and water of ratios 2:3, 3:4 and 7:5. 10 Litres of first and 21 Litres of second bottles are taken. How much quantity from third bottle is to be taken so that final mixture from three bottles will be of ratios 1:1.

If xa+b+1=xa-b+a-ba+b, then x is equal to