Acoin contains 9 grams of nickel and 16 grams of copper, for a total weight of 25 grams. what percentage of the metal in the coin is copper?

64% of the metal in the coin is copper.

Step-by-step explanation:

A coin contains nickel = 9 grams

and copper = 16 grams.

Total weight of the coin = 16 + 9 = 25 grams

Now we have to calculate the percentage of copper in the coin.

Therefore, × 100

                = 0.64 × 100

                = 64%

Hence 64% of the metal in the coin is copper.

because linear equations are a lot simpler than quadratics equations, and linear equations formula is a lot easier to memorize. that's why i think they're harder.