Answer:
4
Step-by-step explanation:
Let's say B is the number of boys and T is the number of teachers.
T / (B + 18) = 2/21
B/18 = 4/3
Solve the second equation for B.
B = 24
Plug into the first equation to find T.
T / (24 + 18) = 2/21
T = 4
Answer:
Hello,
Step-by-step explanation:
y-intercept: x=0 ,f(0)=-10

x-intercepts are: 5,1,2.
The required percentage error when estimating the height of the building is 3.84%.
<h3>How to calculate the percent error?</h3>
Suppose the actual value and the estimated values after the measurement are obtained. Then we have:
Error = Actual value - Estimated value
Given that,
An estimate of the height, H meters, of a tall building can be found using the formula :
H = 3f + 15
where the building is f floors high.
f = 85
The real height of the building is 260 m.
H = 3f + 15
Put f = 85 in the above formula
H = 3(85) + 15
H = 270 m
Error,

So, the required percentage error is 3.84%.
Learn more about percentage error;
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The general formula of a pyramid with any base is 1/3 bh where b is the area of the base and h is the height. In this case, the height of the pyramid is said to be twice the height of the prism, h. Hence the area becomes 1/3 b*2h or equal to option A. 2/3
Answer:
Step-by-step explanation:
i). 

= 8a²
ii).
= 
= 
= 9a²b²c²