Answer:
(x, y) = (7, -7)
Step-by-step explanation:
You can eliminate y by adding the two equations:
(3x -y) +(3x +y) = (28) +(14)
6x = 42 . . . . simplify
x = 7 . . . . . . divide by 6
You can eliminate x by subtracting the two equations:
(3x +y) -(3x -y) = (14) -(28)
2y = -14 . . . . simplify
y = -7 . . . . . . divide by 2
The solution is (x, y) = (7, -7).
Let x be the number of pizzas purchased. For each card, write an expression for the amount of money left on the card after purchasing x pizzas.
For Keith
Keith received a gift card of $90 for a pizza restaurant. The restaurant charges $15 per pizza.
x numbers of pizza costs = $15x
Hence, the amount of money left on Keith's card after purchasing x pizzas =
$90 - $15x
For Mary,
Mary received a gift card of $110 for a different pizza restaurant. The restaurant charges $20 per pizza.
Hence, x number of pizzas cost =$20 × x
= $20x
Therefore, the amount of money left on Mary's card after she buys x pizzas =
$110 - $20x
Amount of money left on Keith's card in dollars = __________
Amount of money left on Mary's card in dollars=____________
Write an equation to show that the two cards have the same amount of money left on them [don't know how to do this part.
To find the equation that shows that the two cards have the same amount of money =
Equation 1 = Equation 2
$90 - 15x = $110 - 20x
Collect like terms
-15x + 20x = $110 - $90
5x = 20
x = 20/5
x = 4
Hence, anytime Keith and Mary buys 4 pizzas their gift card will have the same amount of money left on them.
Answer:
Step-by-step explanation:
7/8 is 63/72
5/12 is 25/60
4/18 is 8/36
Answer:
CI 99% = ( - 0.0009 ; 0.0541 )
Step-by-step explanation:
Sample 1 New Yorkers
sample size n₁ = 558
x₁ = 193
p₁ = x₁/n₁ = 193/ 558 p₁ = 0.3458 q₁ = 1 - p₁ q₁ = 1 - 0.3458
q₁ = 0.6542
Sample 2 Californians
sample size n₂ = 614
x₂ = 196
p₂ = x₂/n₂ = 196 / 614 p₂ = 0.3192 q₂ = 1 - p₂ q₂ = 1 - 0.3192
q₂ = 0.6808
CI 99 % means significance level α = 1 αα% α = 0.01
α/2 = 0.005
In z-table we look for z score for 0.005 z (c) = 2.57
CI 99 % = [ ( p₁ - p₂ ) ± z(c) * √( p₁*q₁)/n₁ + ( p₂*q₂)/n₂
p₁ - p₂ = ( 0.3458 - 0.3192 ) = 0.0266
√( p₁*q₁)/n₁ + ( p₂*q₂)/n₂ =√ 0.3458*0.6542)/558 + 0.3192*0.6808)/614
√( p₁*q₁)/n₁ + ( p₂*q₂)/n₂ = √ 4.05*10⁻⁴ + 3.54 * 10⁻⁴
√( p₁*q₁)/n₁ + ( p₂*q₂)/n₂ = 10⁻² * √7.59 = 10⁻² * 2.75
Then:
CI 99 % = 0.0266 ± 2.75 * 10⁻²
CI 99% = 0.0266 ± 0.0275
CI 99% = ( - 0.0009 ; 0.0541 )
No, this would not be a biased question unless the people asked were all Thai people or all Chinese people. Then the information would be skewed because naturally, Chinese people would favor Chinese food and same for Thai.
