4. the call letters for all radio stations in the united states start with either a w (east of the mississippi river) or a k (west of the mississippi river) followed by three other letters that
can be repeated. how many different call letters are possible?

 There are 35152  different call letters are possible.

Step-by-step explanation:

Given : The call letters for all radio stations in the United States start with either a W (east of the Mississippi River) or a K (west of the Mississippi River) followed by three other letters that  can be repeated.

i.e.The total characters = 4

The choices for first letter = 2  (either W or K)

The choices for rest of other letters = 26  (English alphabets has 26 letters)

Then, the number of different call letters are possible =2 x 26 x 26 x 26

=35152

Therefore , there are 35152 different call letters are possible.

yes

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)