Answer:
The number of bacteria after
will be 
Step-by-step explanation:
Given the initially 30 bacteria present in the culture.
Also, the number of bacteria got doubled every hour.
So, using the equation

Where
is number of bacteria after
hours.
is bacteria present initially.
is the common ration, in our problem it is given that bacteria doubles every hour. So, 
And
is the number of hours. In our problem we need amount of bacteria at the end of
hours. So, 
Plugging values in the formula we get,

So, number of bacteria after
will be 
2.40/6 I believe tell me if it is right
<u>Answer:</u>

<u>Solution:</u>
Given: x=30
To solve: 
On substituting the value of x,

On dividing 30 and 5 we get,

So, the option is 15.
<u>Answer:</u>
-10,1,19
<u>Step-by-step explanation:</u>
<u></u>
x+y+z = 10 (Equation 1)
2y-x= 12 (Equation 2)
x-y+2z = 7 (Equation 3)
(Equation 2): -x = -2y+12
x = 2y-12 (Equation 4)
(Equation 1) - (Equation 3): 2y-z = 3
-z = -2y+3
z = 2y-3 (Equation 5)
Substitute (4) and (5) into (1)
x+y+z = 10
(2y-12)+y+(2y-3) = 10
5y-15 = 10
5y = 5
y=1
Substitute y=1 into (2)
2y-x= 12
2(1)-x= 12
2-x= 12
-x= 12-2
-x= 10
x= -10
Substitute y=1 and x=-10 into (1)
x+y+z = 10
-10+1+z = 10
z-9 = 10
z = 10+9
z = 19
Order: x = -10, y = 1, and z = 19
The ratio can be determined as,

Thus, the requried ratio is 7:12.