Heather has made 28 note cards for her friends. She plans to send out a total of forty cards. What percentage of the cards has she finished?

70%

Step-by-step explanation:

i don't really know how to explain it, but to double check .70 x 40 = 28 :)

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)

hey! so 1 (25) out of 4 (100) is 25 so your answer is 25%. it's like quarters!