The chemical acidity of a solution is measured in units of pH: , where  is the hydrogen ion concentration in the solution. If a sample of rain has a pH of 3.4, how many times higher is its 

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A.
B.
C. 7
D.
E.

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Answer: A

Mathematics

Solve the problem.A zoom lens in a camera makes a rectangular image on the film that is 6 cm × 5 cm. As the lens zooms in and out, the size of the image changes. Find the rate at which the area of the image begins to change (dA/df) if the length of the frame changes at 0.6 cm/s and the width of the frame changes at 0.2 cm/s.

A.  m2/s
B. 4.2 m2/s
C. 0.84 m2/s
D. 4.6 m2/s

Find the exact circular function value.sin 

A.
B. - 
C. - 
D.

Write as a decimal number rounded as indicated.; Round to the nearest thousandth.

A. 0.667 B. 0.264 C. 0.268 D. 0.267

Add.1.448 + 5.3

A. 6.738 B. 6.858 C. 6.748 D. 6.749