.) What is Mary's biking speed in miles per hour? 10/½ =

Multiply 10 by the number of ½ hours in 1 hour

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)

47 - 90 = 43

43 - 180 = x

x = 137