Relative density, or specific gravity, is the ratio of the density of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water at its densest; for gases, the reference is air at room temperature.
Answer:
Number of gallons =2 gallon
Explanation:
given data:
rate of gasoline ineurope = 5 euro per liter
total money to buy gasoline = 40 euro
total gasoline an american can buy in europe 
= 8 litres of gasoline
As given in the question 1 ltr is 1 quarts therefore
Total no. of quarts is 8 quarts
As from question 4 quarts is equal to one gallon, hence
Number of gallons
Your question has been heard loud and clear.
Well it depends on the magnitude of charges. Generally , when both positive charges have the same magnitude , their equilibrium point is towards the centre joining the two charges. But if magnitude of one positive charge is higher than the other , then the equilibrium point will be towards the charge having lesser magnitude.
Now , a negative charge is placed in between the two positive charges. So , if both positive charges have same magnitude , they both pull the negative charge towards each other with an equal force. Thus the equilibrium point will be where the negative charge is placed because , both forces are equal , and opposite , so they cancel out each other at the point where the negative charge is placed. However if they are of different magnitudes , then the equilibrium point will be shifted towards the positive charge having less magnitude.
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