Here's how you would solve it. The process should be the same for the others.
A baseline for experimental investigation is provided by an hypothesis. This is a must before conducting experiments. Also, it is the hypothesis that is being proved by doing the experiments. So, hypothesis is very important in research studies. Hope this answers the question.
To solve this we use the equation,
M1V1 = M2V2
where M1 is the concentration of the stock
solution, V1 is the volume of the stock solution, M2 is the concentration of
the new solution and V2 is its volume.
65 x V1 = 2 x 200 L
V1 = 6.15 L
The sand provides a rough surface on top of the ice for the cars' tires to grip onto. It provides more friction. Salt melts the ice and often provides more friction (the disadvantage is that it eats concrete!).
