22. Restaurants At Morgan's Fine Cuisine, meals are served a la carte. That is, each item on the menu is priced separately. Jackie and Ted Parris went to Morgan's to
celebrate their anniversary. Jackie ordered prime rib, 2 side dishes, and a roll. Ted
ordered prime rib, 3 side dishes, and 2 rolls. Jackie's meal came to $36 and Ted's
meal came to $44. If the prime rib is three times as expensive as a side dish, what
is the cost of each item?

Cost of a side dish = $ 7

Cost of a roll = $1

Cost of prime rib = $21

Step-by-step explanation:

Let x = cost of a side dish , y= cost of a roll

Then, cost of a prime rib = 3x

Jackie's meal : prime rib, 2 side dishes, and a roll, it came to $36

i.e. 3x+2x +y = 36

⇒ 5x+y=36   (i)

Ted's meal : prime rib, 3 side dishes, and 2 rolls, it came to $44.

i.e. 3x+3x +2y = 44

⇒6x+2y=44

⇒ 3x+ y= 22   (ii)  [divide both sides by 2]

Subtract (ii) from (i), we get

2x= 14

⇒ x=7               [divide both sides by 2]

Put x=7 in (ii), 3(7)+y=22

⇒ 21+y=22

⇒  y =22-21

⇒ y= 1

So, cost of a side dish = $ 7

cost of a roll = $1

cost of prime rib = 3x $7 = $21

answer: expected value of x = 1.0

step-by-step explanation:

p(x=0) = 0.25

p(x=1) = 0.50

p(x=2) = 0.25

expected value for x = 0×0.25 + 1×0.5 + 2×0.25 = 1.0