Hello!
A sample of Bromine-82 begins at 80 mL. We are given that this value will decrease by half of its current amount every 35 hours. First, we'll determine the number of times that 35 goes into 140. This will reveal the number of times we should divide the sample by 2:
140 ÷ 35 = 4
We have now proven that there are 4 periods of 35 hours in 140 hours. This means that we will divide the sample in half a total of 4 times, as follows:
1. 80 ÷ 2 = 40
2. 40 ÷ 2 = 20
3. 20 ÷ 2 = 10
4. 10 ÷ 2 = 5
We have now proven that an 80 mL sample of Bromine-82 will be reduced to only 5 mL after 140 hours. Therefore, the correct answer is 5 mL.
I hope this helps!
240÷6=40 so the answer would be "The train is traveling 40 miles per hour."
I got 9.75 hope it's right
First picture)
I: 5x+2y=-4
II: -3x+2y=12
add I+(-1*II):
5x+2y-(-3x+2y)=-4-12
8x=-16
x=-2
insert x=-2 into I:
5*(-2)+2y=-4
-10+2y=-4
2y=6
y=3
(-2,3)
question 6)
I: totalcost=115=3*childs+5*adults
II: 33=adults+childs
33-adults=childs
insert childs into I:
115=3*(33-adults)+5*adults
115=99-3*adults+5*adults
16=2*adults
8=adults
insert adults into II:
33-8=childs
25=childs
so it's the last option
question 7)
a) y<6 and y>2 can also be written as 2<y<6, so solution 3 exist for example
b) y>6 and y>2 can also be written as 2<6<y, so solution 7 exist for example
c) y<6 and y<2 inverse of b: y<2<6, so for example 1
d) y>6 and y<2: y<2<6<y, this is impossible as y can be only either bigger or smaller than 2 or 6
so it's the last option
question 8)
I: x+y=12
II: x-y=6
subtract: I-II:
x+y-(x-y)=12-6
2y=6
y=3
insert y into I:
x+3=12
x=9
(9,3)
question 9)
I: x+y=6
II: x=y+5
if you take the x=y+5 definition of II and substitute it into I:
(y+5)+y=6
which is the second option :)
Brent 1 ton is 2000 lbs /5= 400 lbs
Nina 500 lbs
So Nina 's truck can carry more
