1 Benny and Marla have been dating for years, and they love to go to the movies.

Question

1  Benny and Marla have been dating for years, and they love to go to the movies. At first, Benny was shocked at Marla’s “healthy appetite.” Movie after movie, Marla would polish off several popcorns and sodas. Being an old-fashioned guy, Benny has always insisted on paying for their movie dates. There are two theaters in town: SkyHi and Xpensive. SkyHi charges $9 per movie ticket, $5 per popcorn bag, and $3 per glass of soda. Xpensive charges $8 per movie ticket, $6 per popcorn bag, and $2.80 per glass of soda. Over the years, Benny has figured out that, per movie, Marla eats an average of 4.2 bags of popcorn with a standard deviation of 1.2 bags and drinks an average of 2 sodas with a standard deviation of 0.5 sodas. Let X = the number of bags of popcorn consumed by Marla during a movie outing and Y = the number of pops consumed by Marla during a movie outing. Now suppose that Marla no longer drinks soda. She will only drink water, which is free. What is the variance in Benny’s movie outing expense for Marla for SkyHi? (Do not include Benny’s own movie ticket cost or the cost of the soda/popcorn that he will consume.)

Explanation / Answer

Benny's earlier cost for movie outing in SkiHi = 9+ 5x+ 3y

Benny's new cost for movie outing in SkiHi = 9 + 5x

Where x has mean 4.2 snd standard deviation of 1.2

Variance in Benny's movie outing expence for Marla for SkiHi = (5* 1.2)^2 = 36

note: variance is square of standard deviation

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