Mark wanted to buy a phone for $200. the phone was then put on sale for 10% off of its price. the next day mark discovered that the phone had an additional 30% off of its sales price. what was the percent of discount from when mark bought it versus it's original price?

answer: true

step-by-step explanation:

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)