Barbara is learning to speak a foreign language. she already knows 16 words in the foreign language. her goal is to know a total of 100 words. over the summer, she will learn 4 new words each day. part a. write an equation that can be uesd to determine the number of days it will take barbara to reach her goal of 100 words. be sure to define the variable in your equation. * your answer part b. how many days will it take barbara to reach her goal?