A glass was filled with 10 ounces of water, and 0.02 ounce of the water evaporated each day during a 20-day period. What percent of the original amount of water evaporated during this period? Choose the correct choice from the following answers.
A) 0.004 %  B) 0.02 %  C) 0.2 %  D) 4 %  E) 40 %

Rationale: we are given that 0.02 ounces of water evaporated each day . furthermore , we know that this process happened over a 20 - day period . to calculate the total amount of water that evaporated during this time frame we need to multiply 0.02 by 20 . this gives us : 0.02 x 20 = 0.4 ounces finally , we are asked for “ what percent ” of the original amount of water evaporated during this period . to determine this percentage , we have to make sure we translate the expression correctly . we can translate it to : ( amount evaporated / original amount ) x 100 % ( 0.4 / 10 ) x 100 % ( 4 / 100 ) x 100 % = 4 % answer d
Answer: D