On a school trip, the ratio of the teachers to students is 2:21. The ratio boys to girls is 4:3. If there are 18 girls girls on the trip, how many teachers are there?

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

guess at question:

a vertical line intersects the graph of g(x,y) = 0 at two points. what conclusion follows about the function f(x) implicitly defined by g(x,f(x)) = 0?

the domain of f(x) cannot include the x coordinate of any such vertical line.

informally, f(x) is not a function, and

g(x,y)=0 cannot be solved for y uniquely.

the relation r = {(x,y) such that g(x,y) = 0} is a function if

for all (a,b) ∊ r and (c,d) ∊ r, a=c implies b=d.

step-by-step explanation: