Answer:
5.6 days
Step-by-step explanation:
We are given;
Initial Mass; N_o = 25 g
Mass at time(t); N_t = 25/2 = 12.5 (I divide by 2 because we are dealing with half life)
k = 0.1229
Formula is given as;
N_t = N_o•e^(-kt)
Plugging in the relevant values;
12.5 = 25 × e^(-0.1229t)
e^(-0.1229t) = 12.5/25
e^(-0.1229t) = 0.5
(-0.1229t) = In 0.5
-0.1229t = -0.6931
t = -0.6931/-0.1229
t = 5.6 days
Let's check. 6 one-dollars = $6 15 five-dollars = $75 9 ten-dollars = $90 Add them all up to get $171, so that is correct. Add the number of one-dollar bills and the number of ten-dollar bills together. 6 + 9 = 15, which is the number of five-dollar bills, so that is correct as well. Add all the numbers of bills together, 6 + 9 + 15 = 15 + 15 = 30, so that is correct
Answer:
(6,-4)
Step-by-step explanation:
-3x-9y = 18 (equation 1)
4x+3y = 12 (equation 2)
multiply equation 2 by 3, and add it to equation 2
-3x-9y = 18
12x+9y = 36
-----------------
X's cancel out
9x = 54
Divide both sides by 9
x = 6
Plug in 6 for x in any of the original equations
(Plugging into Equation 2)
4(6)+3y = 12 Multiply 4(6)
24+3y = 12 Subtract 24 from both sides
3y = -12 Divide 3 on both sides
y = -4
Therefore the solution is (6,-4).
Answer:
Convert fraction (ratio) 39 / 40 Answer: 97.5%
Step-by-step explanation:
