Quantitative Aptitude - Arithmetic Ability Questions

A train crosses a 375 m long platform in 27 seconds. How long was the train if it was travelling at the speed of 70 kmph?

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

Find k, if the line 4x - y = 1 is perpendicular to the line 5x - ky = 2?

If 3x + 5y + 7z = 49 and 9x + 8y + 21z = 126, then what is the value of y?

Find the odd one out among the following.

What fraction of 2 hours is 12 seconds?

If a regular polygon has 6 sides then the measure of its interior angle is greater than the measure of its exterior angle by how many degrees?

If (4a-3)2=0,then the value of 64a3+12a+13 is