Making a Coin Jump Into a Cup

An athlete making a high jump to clear the bar at a certain height.

When a person jumps up,

Six coins of equal weight made up of an alloy of gold and silver are melted to make another set of six coins .The ratio of gold and silver in a coins is in ratio of 2:1 , in two coins this ratio is 3:5 , and for ramaining coins this ratio is 7:5 .Find the ratio of gold and silver in new coins ?

Carry out the following osmosis experiment: Take four peeled potato halves and scoop each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup in a trough containing water. Now, (a) Keep cup A empty (b) Put one teaspoon sugar in cup B (c) Put one teaspoon salt in cup C (d) Put one teaspoon sugar in the boiled potato cup D. Keep these for two hours. Then observe the four potato cups and answer the following: Explain why water gathers in the hollowed portion of B and C