An archaeologist finds the 14C in a sample of 3.10 g of material ...

[nummyann]

An archaeologist finds the 14C in a sample of 3.10 g of material to be decaying at 107 counts per second. A modern 1.00-g sample of the same material decays at 151 counts per second. The half-life of 14C is 5730 y. How old is the sample?
 
  A) 12,200 y
  B) 8460 y
  C) 25,100 y
  D) 12,600 y

Question 2

A porch roof that slopes upward at 45 measures 3.0 m  5.0 m. It is covered with a slab of insulating material that is 2.0 cm thick.
 
  If the density of the insulation is 15 kg/m3, what is the weight of the insulation, in pounds, on the roof? (1.00 kg weighs 2.2 lb and density is mass per unit volume.)
  A) 4.5 lb
  B) 9.0 lb
  C) 20 lb
  D) 990 lb
  E) 9.9 lb

[cuttiesgirl16]

Answer to Question 1

A

Answer to Question 2

E

[nummyann]

Both answers were spot on, thank you once again

[cuttiesgirl16]

Great! Please up vote