4. The gallons of gasoline used on a car trip varies directly as the number of miles driven. If 25 gallons of gasoline has been used after driving 700 miles, how many
gallons of gasoline would be used after driving 1,000 miles?

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)

2nd one in the first row is correct

hi do you need an answer for your question?

step-by-step explanation: