How much of a radioactive kind of xenon will be left after 15 days if the half-life is 5 days and you start with 96 grams

12 grams

Step-by-step explanation:

15/5 = 3 half lives

(1/2)³ = 1/8 of the original amount will remain

96 * 1/8 = 12 grams

Step-by-step explanation:

Radioactive decay problems are very similar to compound interest formulas, except the rate is subtracted from one, instead of adding to one.

I.e.

mass at time t, m(t) = M (1 - r)^(t/h)

where

M = initial mass (grams)

m (t) mass left at time t (grams)

h = half-life in number of days

r = 0.5 from "half-life"

t = time lapse in number of days

Here

M = 96

h = 5

t = 15

m(15) = 96(1-0.5)^(15/5)

= 96 (1/2)^3

= 12 grams

c

step-by-step explanation:

answer: c, the green line

step-by-step explanation:

there is no black line, eliminate b.

simple interest implies periodic payments, but the red line shows no payments, eliminate d.

simple interest has equal payments. if paid say every day, the graph is about a straight line (actually a stairstep).

the yellow line is not straight, eliminate a.

check: the green line is straight, answer is c.

simple interest with positive interest rate gives a straight line sloping up to the right. green line:

g(t) = $100 + ($200-$100) ÷ (20 years) × (t years)

= $100 + (4%/year) × ($100)(t years)

incidentally, the yellow line curving upward represents continuously compounded interest

y = $100 × 2^(t years / (14 assuming the yellow line hits $200 at 14 years. 2^0 is 1, so y(0) = $100; 2^(14/14) is 2, so y(14) = $200.