college algebra - please help The half-life for thorium-227 is 18.72 days. The amount A (in grams) of thorium-227 after t days for a 10-gram sample is given by A(t)=10⋅0.5^t/18.72 How long will it take before 4 grams of thorium-227 is left in the sample? Round your answer to the hundredths place. _days

On the way home from visiting his family, vincent’s plane cruised at an altitude of 3.2 × 10^4 feet. he had heard that a man named felix baumgartner skydived from an altitude of 1.28 × 10^5 feet. vincent wants to know how much higher felix went on his skydiving trip. question 1 you have already seen how adding numbers works in either scientific notation or standard notation. but can you subtract numbers in scientific notation and get the same results as subtracting in standard notation? to find out, first solve vincent’s problem in standard notation. part a write the cruising altitude of vincent’s plane in standard notation.