The atomic number of nitrogen is 7. Nitrogen-15 is heavier than nitrogen-14 because the atomic nucleus of nitrogen-15 contains how many neutrons?.

The recommended daily calcium intake for a 20-year-old is 1,000 milligrams (mg). one cup of milk contains 299 mg of calcium and one cup of juice contains 261 mg of calcium. which of the following inequalities represents the possible number of cups of milk m and cups of juice j a 20-year-old could drink in a day to meet or exceed the recommended daily calcium intake from these drinks alone?

The inconsistency of behaviors also makes personality test scores predictors of behaviors.

Raul has one solution that is 20% acid by volume and one solution that is 50% acid by volume. he plans to mix together some of each solution to create 30 milliliters of a solution that is 40% acid by volume. how many milliliters of the 20% acid solution should raul use to create the 40% acid solution? can someone explain this to me? i know that the answer is 10 milliliters, but i don't know how to get it.