Find the percent of change if the original cost was $5 and the new cost is $1.
Decrease 80%
Decrease 400%
Increase $4
Decrease $4

Decrease 80%

Step-by-step explanation:

Since, new cost is less than the original cost, hence there will be a decrease of 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)