An 18 gram sample of a substance that's used to detect explosives has a k-value of 0.215. Find the substance's half-life in days. Round your answer to the nearest tenth. HELP PLEASE

Angel entered a triathlon (a three-part race). he swam 1 mile, rode his bike 30 miles, and ran 10 miles. how far did he go altogether? a. 11 miles b. 123 miles c. 41 miles d. 40 miles

This is so hard and it’s for a test

An energy drink company claims that its product increases students' memory levels. to support its claims, the company issues advertisements claiming that 8 out of 10 people (chosen randomly from across the country) who tried their product reported improved memory. the missing component in this study is a .