If the half life of a substance is 4 weeks, how long will it take for 400 mg of this substance to decay to 25 mg?

When a formula is solved for a particular variable, several different equivalent forms may be possible. if we solved a=1/2bh for h, one possible correct answer is h=2a/b . which one of the following is not equivalent to this? a. h= 2(a/b) b. h= 2a(1/b) c. h= a/1/2b d. h= 1/2a/b

At a lunchron, guests are offered a selection of five different grilled vegetables and four different meats. in how many waya could one choose three vegetables and two meats?

Solve the equation - 2(m -30) = -6m a-15 b-13 c-8 d8