Try this solution (if it is possible, check it in other sources):
1. for m_Tarzan=75kg., initial_height=4m., end_height=0 m. and g=10 N/kg. Energy is:

2. The same value of Energy is applied for m_Tarzan+Jane=75+50=125 kg.:

3. According to the formula of the Speed:
Speed=sqrt(6000/125)=sqrt(48)=4sqrt(3)≈4*1.71=6.84 (m/s)
Answer: 6.84 (m. per sec.)
A droplet of pure mercury has a density of 13.6 g/cm3. What is the density of a sample of pure mercury that is 10 times as large as the droplet?
Answer: In this case the density will remain constant for both droplets. The reason being that volume will not change the density of the material. The only way of changing it is by changing its state. If you increase the volume then the mass will also increase. Leaving the density the same.
I hope it helps, Regards.
I think this is shown in the fine print on the second sheet . . .
The question starts out by saying that the scale uses <u>two</u> 3V cells <u>in series</u>.
That makes the total battery voltage 6 volts.
0.12 milliamperes = 0.00012 Amperes.
Resistance = (voltage) / (current in Amperes).
Resistance = 6 / 0.00012 = 50,000 Ω