Amass on a spring oscillates with a certain amplitude and a certain period t. if the mass is doubled, the spring constant of the spring is doubled, and the amplitude of motion is doubled, the period:

The period stays the same.

Explanation:

The period "T" of a oscilating system composed by a amss on a spring is described by the following equation:

Where 'm' is the mass and 'k'is the spring constant.

From the equation, changes in amplitude don't interfere in the period. If both 'm' and 'k' are doubled:

The period stays the same.

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.