James has at least 30 coins in his piggy bank. The coins are all nickles and dimes for a total of at most $3. Write a system of linear inequalities that can be used to find the number of nickles and dimes in the piggy bank.
nickles = x dimes = y x+y > or equal to 30 .05x + .10y < or equal to 3
In recent years certain environmentalist groups have pointed to the use of artificial golf courses near large bodies of water as an alternative to natural grass, why could this be?
Natural grass requires the use of fertilizers which contain sulfates and phosphates within them. When these run off into the water it causes eutrophication, the overgrowth of algae that decreases dissolved oxygen within the body of water effectively killing off fish.
The earth's magnetic fields shift poles every so often, what is some evidence of this?
The main evidence to this would be in the mid-ocean ridges. These ridges release magma as they expand, and this magma contains magnetized iron particles. The direction the magnetized particles point changes as the earths magnetic fields shift poles.