You earned the following marks (all equally weighted) on your first five tests: 28, 36, 38, 41, and 44. What mark would you have to get on the next test in order to bring
your test mean average up to 80%?

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)

-232

step-by-step explanation: