Answer:
5 felt pads.
7 cards.
Step-by-step explanation:
Remark
- The total number of items is 12
- So let the felt sheets be x
- Let the cards = y
Equations and Solution
x + y = 12
Now the price is 7.75 that she has to pay for the 12 items. She wants to come back with 0 dollars.
0.5x + 0.75y = 7.75 Multiply this equation by 2
x + 1.5y = 15.50 write the first equation underneath and subtract.
<u>x + y = 12</u>
.5y = 3 Divide by 0.5
y = 3/0.5
y = 7
So she can get 7 cards.
x + y = 12
x + 7 = 12
x = 12 - 7
x = 5
So she can buy 5 felt pads.
Answer:
15cm
Step-by-step explanation:
All you need to do for this is divide the perimeter (60) by the number of sides on a square (4). 60÷4=15
Answer:
The 99% two-sided confidence interval for the average sugar packet weight is between 0.882 kg and 1.224 kg.
Step-by-step explanation:
We are in posession of the sample's standard deviation, so we use the student's t-distribution to find the confidence interval.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 16 - 1 = 15
99% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 35 degrees of freedom(y-axis) and a confidence level of ). So we have T = 2.9467
The margin of error is:
M = T*s = 2.9467*0.058 = 0.171
In which s is the standard deviation of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 1.053 - 0.171 = 0.882kg
The upper end of the interval is the sample mean added to M. So it is 1.053 + 0.171 = 1.224 kg.
The 99% two-sided confidence interval for the average sugar packet weight is between 0.882 kg and 1.224 kg.
Answer:
0% probability that a customer will be exactly 7.50 minutes in the record store.
Step-by-step explanation:
Uniform probability distribution:
An uniform distribution has two bounds, a and b.
The probability of finding a value of at lower than x is:
The probability of finding a value between c and d is:
The probability of finding a value above x is:
The uniform distribution is a continuous distribution, which means that the probability of an exact outcome is zero.
Uniformly distributed between 3 and 12 minutes.
This means that
What is the probability that a customer will be exactly 7.50 minutes in the record store?
Continuous distribution, so:
0% probability that a customer will be exactly 7.50 minutes in the record store.
Answer:
a) the probability that the minimum of the three is between 75 and 90 is 0.00072
b) the probability that the second smallest of the three is between 75 and 90 is 0.396
Step-by-step explanation:
Given that;
fx(x) = { 1/5 ; 50 < x < 100
0, otherwise}
Fx(x) = { x-50 / 50 ; 50 < x < 100
1 ; x > 100
a)
n = 3
F(1) (x) = nf(x) ( 1-F(x)^n-1
= 3 × 1/50 ( 1 - ((x-50)/50)²
= 3/50 (( 100 - x)/50)²
=3/50³ ( 100 - x)²
Therefore P ( 75 < (x) < 90) = ⁹⁰∫₇₅ 3/50³ ( 100 - x)² dx
= 3/50³ [ -2 (100 - x ]₇₅⁹⁰
= (3 ( -20 + 50)) / 50₃
= 9 / 12500 = 0.00072
b)
f(k) (x) = nf(x) ( ⁿ⁻¹_k₋ ₁) ( F(x) )^k-1 ; ( 1 - F(x) )^n-k
Now for n = 3, k = 2
f(2) (x) = 3f(x) × 2 × (x-50 / 50) ( 1 - (x-50 / 50))
= 6 × 1/50 × ( x-50 / 50) ( 100-x / 50)
= 6/50³ ( 150x - x² - 5000 )
therefore
P( 75 < x2 < 90 ) = 6/50³ ⁹⁰∫₇₅ ( 150x - x² - 5000 ) dx
= 99 / 250 = 0.396