English, thankfully, is a language without many gender-related problems, but some do exist, and being gender neutral in MBA application essays can be important. In general, a key way to avoid such problems is to pluralize-talk about groups rather than individuals. Consider the following examples:
a. Today's manager must be financially literate to do his job well.
b. Today's manager must be financially literate to do his/her job well.
c. Today's managers must be financially literate to do their jobs well.
In (a), the sentence is poor because it is not gender neutral. Simply put, avoid writing his and assuming that the manager is a man. When you are talking about a hypothetical manager and don't know that manager's gender, you cannot assume the manager is a man any more than you can assume she is a woman.
Sentence (b) is better because it shows that the writer is sensitive to gender issues and, therefore, has made sure to insert /her after his. However, using his/her, him/her, he/she (or s/he) and other such constructions can make essays unnecessarily cumbersome and can also disrupt an essay's style or rhythm for the reader.
Sentence (c) is, therefore, the best of the three sentences. Words that entail gender considerations when singular lose such considerations when pluralized: his/her becomes their,him/her becomes them, he/she or s/he becomes they. Pluralizing gender-laden pronouns will allow you to avoid this awkward problem-and, as you may have noticed, will save word count as well.