What letter or symbol that represents some unknown value

2men and 7 boys can do a piece of working 4 days. it is done by 4 men and 4 boys in 3 days how long would it take for 1man or one boy to do it alone

With these: 18/36 = 1/? missing number change 1 5/8 to improper fraction. change 19/5 to a mixed number.

Do social recommendations increase ad effectiveness? a study of online video viewers compared viewers who arrived at an advertising video for a particular brand by following a social media recommendation link to viewers who arrived at the same video by web browsing. data were collected on whether the viewer could correctly recall the brand being advertised after seeing the video. the results are given below. correctly recalled the brandarrival 409153browsing20484b. conduct the hypothesis test, using the 0.025 level of significance. what is the value of the test statistic? χ2stat=what is the p-value? p-value=is this value significant atα=0.025?