How to find synthesis of data in physics Practice Test

Mary is performing an experiment involving the electromagnetic spectrum. She observes several different types of waves and records their wavelength, frequency, and speed.

A new type of radiation is discovered on the electromagnetic spectrum that has a higher frequency than gamma rays. What would its speed most likely be?

Laura is performing an experiment with a 5kg weight tied to a 3m rope tied to the ceiling as shown:

Laura drops the weight and allows it to swing freely. She measures how long it takes for the weight to return to it's original position (assume no forces outside of gravity are acting upon the pendulum). This is also called one oscillation.

Experiment 1:

Laura created the following table for her first measurement of the pendulum's oscillations.

Experiment 2:

Laura performed the experiment again, this time using a 6kg weight.

Experiment 3:

Laura performed the experiment again, this time using a 3kg weight and a 5m rope.

If Laura recreated experiment 3 using a 5m rope and a 20kg weight, how long would 2 oscillations last?