Check the picture below.
notice, the gift box is just 6 rectangles stacked up to each other at the edges,
left and right, two rectangles of 32x40
top and bottom, two rectangles of 25x32
front and back, two rectangles of 25x40
so, just get the area of all 6 rectangles, add them up, and that's the "surface area" of the rectangular prism, and that's how much paper will be needed to cover it.
Answer:
a) 229 and 305 days
b) 229 days or less
c) 305 days or more
Step-by-step explanation:
The Empirical Rule(68-95-99.7 rule) states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 267
Standard deviation = 19
(a) Between what values do the lengths of the middle 95% of all pregnancies fall?_____________and___________days
By the Empirical rule, 95% of all pregnancies fall within 2 standard deviations of the mean.
So
267 - 2*19 = 229 days
to
267 + 2*19 = 305 days
(b) How short are the shortest 2.5% of all pregnancies?______days or less
95% of all pregnancies fall within 2 standard deviations of the mean. The other 5% are more than 2 standard deviations from the mean. Since the distribution is symmetric, 2.5% is more than 2 standard deviations below the mean(shortest 2.5%) and 2.5% is more than 2 standard deviations above the mean(longest 2.5%). So
267 - 2*19 = 229 days
c) How long do the longest 2.5% of pregnancies last?________days or more
Explanation in b)
267 + 2*19 = 305 days
Answer: x = -0.2651 and y = -0.9759
Step-by-step explanation:
Solution by substitution method
8x+5y= -7
-7x+6y= -4 = 7x-6y=4
Suppose,
8x+5y=-7→(1)
7x-6y=4→(2)
Taking equation (1), we have
8x+5y= -7
⇒8x= -5y -7
⇒x= -5y-7 / 8 →(3)
Putting x= -5y-7 / 8
in equation (2), we get 7x-6y=4
7(-5y-7/8)-6y=4
⇒-35y-49-48y=32
⇒-83y-49=32
⇒-83y=32+49
⇒-83y=81
⇒y= 81 / -83
⇒y= -0.9759→(4)
Now, Putting y= -0.9759 in equation (3), we get
x= -5y-7
x= -5(-0.9759)-7/8
⇒x= 4.8795-7/8
⇒x= -2.1205/8
⇒x= -0.2651
∴x= -0.2651 and y = -0.9759
Ron should receive $7.98. Jerry and Steve each worked for 4 hours, while Ron was one hour late, so he worked for 3 hours. Together, they worked for 4*2+3=11 hours, receiving $29.25 in total. Each hour should be paid 29.25/11=2.66 dollars. Ron worked for three hours, so he should receive 3*2.66=7.98 dollars.
Step-by-step explanation:
L H J because they are all on the same line.