(a)
The binomial distribution can be used because the current situation satisfies all of the following:
1. The probability of success (p=85%) is known and remains constant during the whole experiment
2. The number of trials (n=40) is known and constant.
3. Each trial is a bernoulli trial (success or failure only)
4. All trials are (assumed) independent of each other.
The probability of x successes is therefore
P(X=x)=C(n,x)(p^x)(1-p)^(n-x)
(b) P(X=35) means the probability of 35 successes out of 40 trials at p=0.85
and
P(X=35)=C(40,35)*0.85^35*0.15^5=658008*0.003386*0.00007594
=0.16918
(c) P(X>=35)=∑ P(X=i) for i=35 to 40
=0.16918+0.13315+0.08157+0.03649+0.01060+0.00150
=0.4325
(d) P(X<20)=∑ P(X=i) for i=0 to 19
=0.00000003513 (individual probabilities are very small).
10 times !!!!!!!!!!!!!!!!!!!!!!!!!!!
This is incorrect because 2 + 5.8 = 7.8. And 7.8 does not equal 6. 2 + 4 = 6 is the correct answer. This could be represented by this:
2 + x = 6.
Subtract two from both sides to get:
x = 4.
When substituted back into the equation:
2 + (4) = 6.
The problem ask to calculate the corresponding distance on the new patio where as the the patio will have two long parallel side and an area of 360 square feet and the area of the similar patio is 250 square feet and its long parallel sides are 12.5 feet apart. To calculate this the ratio of the distance of the two polygon is P:Q so it means that the are is also P^2:Q^2 so the ratio of the area is 36:25 so the the distance of the new patio is 18 feet
2x^2 - 2x - 40 = 2x^2 -10x + 8x - 40 = 2x(x - 5) + 8(x - 5)
= (x-5)(2x+8) = 2(x-5)(x+4)
