20x + 15y = 2000
x + y = 115
55+60=115
20 (55) + 15 (60)=2000
1100+900=2000
2000=2000
Answer:
-20+8x
Step-by-step explanation:
Answer:0.75 milligrams will be present in 24 hours
Step-by-step explanation:
Step 1
The formula for radioactive decay can be written as
N(t)=No (1/2)^(t/t 1/2)
where
No= The amount of the radioactive substance at time=0=milligrams
t 1/2= the half-life= 6 hours
t=24 hours
N(t) = the amount at time t
Step 2--- Solving
N(t)=No (1/2)^(t/t 1/2)
=N(t)=12 x ( 1/2) ^ (24/6)
= 12 x (1/2) ^4
= 12 x 0.0625
= 0.75 milligrams
Answer:
d<150
Step-by-step explanation:
If you turn 9 1/3 in to a decimal and 3 1/2 in a decimal also
9 1/3 = 9.3 and 3 1/2 =3.5
9.3+3.5 =12.8
12.8=12 4/5
