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I think it would be C because the equation is y=7x. y=7x is also equal to x=1/7y. If y=45.50, then you would have to divide y by 7, which would equal 6.5.
Answer:

Step-by-step explanation:
Let the function of quantity in the lung of air be A(t)
So 
so, A(t) = Amax sin t + b
A(t) = 2.8t⇒ max
A(t) = 0.6t ⇒ min
max value of A(t) occur when sin(t) = 1
and min value of A(t) = 0
So b = 0.6
and A(max) = 2.2

at t = 2 sec volume of a is 0.6
So function reduce to

and t = 5 max value of volume is represent
so,

when t = 5

so the equation becomes
