Find the substance's half-life, in days.
Round your answer to the nearest tenth.

t = 5.6 day

t =5 days 14 hours 24 minutes

Step-by-step explanation:

Half life is the time it will take for the original value or quantity I'd a particular substance to decrease by half of it's original self.

N = N•e(-kt)

N• = 25

K = 0.1229

Then

N = 25/2 = 12.5

The reason because at the half life , it's original value will decrease to half.

Let's solve for the half life t

N = N•e(-kt)

12.5 = 25e(-0.1229t)

12.5/25 = e(-0.1229t)

0.5 = e(-0.1229t)

In 0.5 =-0.1229t

-0.69314 = -0.1229t

-0.69314/-0.1229 = t

5.6399 = t

To the nearest tenth

5.6 days = t

marco saved more.   he saved $35 more.

step-by-step explanation:

1+2+3+4+5+6+7+8+9+10 = 55

2*10 = 20

55-20 = 35