Acertain element has a half life of 4.5 billion years. (a). you find a rock containing a mixture of the element and lead. you determine that 35% of the original element remains; the other 65% decayed into lead. how old is the rock? (b). analysis of another rock shows that it contains 55% of it's original element; the other 45% decayed into lead. how old is the rock.

With these: 18/36 = 1/? missing number change 1 5/8 to improper fraction. change 19/5 to a mixed number.

According to the 2008 u.s. census, california had a population of approximately 4 × 10^7 people and florida had a population of approximately 2 × 10^7 people. which of the following is true? a. the population of california was approximately two times the population of florida. b. the population of florida was approximately twenty times the population of california. c. the population of florida was approximately two times the population of california. d. the population of california was approximately twenty times the population of florida.

Peyton's field hockey team wins 4 games out of every 7 games played. her team lost 9 games. how many games did peyton's team play?