39×52/3.8×4.9 round the answer to 1 sig fig

Element x decays radioactively with a half life of 8 minutes. if there are 450 grams of element x, how long, to the nearest tenth of a minute, would it take the element to decay to 37 grams?

Areal estate agent earns $32,000 a year plus $1,000 for each apartment he sells. write an equation that shows the relationship between the number of apartments abe sells,n, and the total amount he earns in a year,e. what is the total amount abe would earn from selling 10 apartments in one year

Each month, a shopkeeper spends 5x + 14 dollars on rent and electricity. if he spends 3x−5 dollars on rent, how much does he spend on electricity? for which value(s) of x is the amount the shopkeeper spends on electricity less than $100? explain how you found the value(s).