C and D are units of length or distance.
A is a measured angle.
B is a unit of angular measurement.
If the soloist produces "x" decibels and the 10-person choir produces "y" decibels, combined they will produce "x+y" decibels.
The second choir has 90 additional singers, we base our description on the first choir. If a 10-person choir produces "x+y" decibels, then the 90 person choir produces 10 (x+y) decibels.
Can you please stop pasting this question, just go to his profile and ask him.
You can make sure there's no change in volume by keeping
your gas in a sealed jar with no leaks. Then you can play with
the temperature and the pressure all you want, and you'll know
that the volume is constant.
For 'ideal' gases,
(pressure) times (volume) is proportional to (temperature).
And if volume is constant, then
(pressure) is proportional to (temperature) .
So if you increase the temperature from 110K to 235K,
the pressure increases to (235/110) of where it started.
(400 kPa) x (235/110) = 854.55 kPa. (rounded)
Obviously, choice-b is the right one, but
I don't know where the .46 came from.