The half-life of radium is 1690 years. If 20 grams are present now, how much will be present in 340 years? grams

The perimeter of a square is80-64y units. which expression can be used to show the side length of one side of the square?

Prove that the sum of two consecutive exponents of the number 5 is divisible by 30.if two consecutive exponents are 5n and 5n + 1, then their sum can be written as 30.

How many heads would you expect if you flipped a coin twice? first, fill in the table below with the correct probabilities. hint: the sample space for flipping a coin twice is {hh, ht, th, tt}. a = b = c = f