An ideal gas is compressed isothermally to one-third of its initial volume. The resulting pressure will be

(A) three times as large as the initial value.
(B) less than three times as large as the initial value.
(C) more than three times as large as the initial value.
(D) equal to the initial value.

(A) three times as large as the initial value.

Explanation:

Boyle law states that the pressure is inversely proportional to volume if we kept the temperature constant.

       (1)

here and are the initial pressure and volume.

and are the final pressure and volume respectively.

now

by putting these values in equation 1.

hence it is proved that " if the volume is decreased to one third of its original value then the pressure will be three times larger then its initial value".

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)