Casey has $21.40 in dimes and quarters. She has a total of 100 coins. How much of each kind of coin does Casey have? Please someone help fast I'm so confused.

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)

14

step-by-step explanation:

14 x 3 = 42

step-by-step explanation:

the answer is  

c.

90.0π cm^2

hope you got it.