Which number below best represents a depth of seven hundred and five-tenths meters below the ground?

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?

The table shows the total distance that myra runs over different time periods. which describes myra’s distance as time increases? increasing decreasing zero constant

How to do this , and can some one explain