A Lens Has a Focal Length of 56

Multiple Choice

A lens has a focal length of 56.2 cm in air.If this lens were immersed in water,what focal length would result? The index of refraction of the lens is 1.96 and that of water is 1.333.The focal length of a thin lens with index n₁ submerged in a liquid with index n₂ is given by the modified lens-maker's formula:
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A) 115 cm
B) 27.5 cm
C) 169 cm
D) 82.6 cm
E) 61.0 cm