In which of these sentences are quotation marks used incorrectly?
a. i just read a magazine article called "life is learning."
b. allen asked, "will you be there at 8: 30, as you promised? "
c. have you no shame sir," he said, his eyes narrowing."
d. "this is too much! " she said, "i will not abide it! "

step-by-step explanation:

the original amount doesn't ''re just looking for the time it takes for 1/2 of the substance to we have

(1/2) =)     take the ln   of both sides

ln (1/2)   = )   and we can write

ln(1/2) = ) lne     and lne   = 1     so we have

ln(1/2) = -.1092t     divide both sides by -.1092

t = ln(1/2)/-.1092 = about 6.347 days = about 6.3 days (rounded)