A marketing company that relies on calling mobile phones, wanted to research if age group and type of response, were independent. The company took a random sample of mobile numbers, categorised them into two different age groups, and then recorded the response as one of three options: call answered, voicemail, call unanswered. The observed frequencies are summarized in the following table.

	Age group
40 years	> 40 years
Response	Unanswered	42	18
Voicemail	55	85
Answered	93	78

What is the total number of respondents in this survey?