Answer:
12/7 = 1 5/7
Step-by-step explanation:
divide 12 by 7 to get 1 with a remainder of 5 and take the denominator and put it under the remainder 5/7 the answer is 1 5/7
Answer:
The chance that there will be exactly 2 heads among the first five tosses and exactly 4 heads among the last 5 tosses is P=0.0488.
Step-by-step explanation:
To solve this problem we divide the tossing in two: the first 5 tosses and the last 5 tosses.
Both heads and tails have an individual probability p=0.5.
Then, both group of five tosses have the same binomial distribution: n=5, p=0.5.
The probability that k heads are in the sample is:
![P(x=k)=\dbinom{n}{k}p^k(1-p)^{n-k}=\dbinom{5}{k}\cdot0.5^k\cdot0.5^{5-k}](https://tex.z-dn.net/?f=P%28x%3Dk%29%3D%5Cdbinom%7Bn%7D%7Bk%7Dp%5Ek%281-p%29%5E%7Bn-k%7D%3D%5Cdbinom%7B5%7D%7Bk%7D%5Ccdot0.5%5Ek%5Ccdot0.5%5E%7B5-k%7D)
Then, the probability that exactly 2 heads are among the first five tosses can be calculated as:
![P(x=2)=\dbinom{5}{2}\cdot0.5^{2}\cdot0.5^{3}=10\cdot0.25\cdot0.125=0.3125\\\\\\](https://tex.z-dn.net/?f=P%28x%3D2%29%3D%5Cdbinom%7B5%7D%7B2%7D%5Ccdot0.5%5E%7B2%7D%5Ccdot0.5%5E%7B3%7D%3D10%5Ccdot0.25%5Ccdot0.125%3D0.3125%5C%5C%5C%5C%5C%5C)
For the last five tosses, the probability that are exactly 4 heads is:
![P(x=4)=\dbinom{5}{4}\cdot0.5^{4}\cdot0.5^{1}=5\cdot0.0625\cdot0.5=0.1563\\\\\\](https://tex.z-dn.net/?f=P%28x%3D4%29%3D%5Cdbinom%7B5%7D%7B4%7D%5Ccdot0.5%5E%7B4%7D%5Ccdot0.5%5E%7B1%7D%3D5%5Ccdot0.0625%5Ccdot0.5%3D0.1563%5C%5C%5C%5C%5C%5C)
Then, the probability that there will be exactly 2 heads among the first five tosses and exactly 4 heads among the last 5 tosses can be calculated multypling the probabilities of these two independent events:
![P(H_1=2;H_2=4)=P(H_1=2)\cdot P(H_2=4)=0.3125\cdot0.1563=0.0488](https://tex.z-dn.net/?f=P%28H_1%3D2%3BH_2%3D4%29%3DP%28H_1%3D2%29%5Ccdot%20P%28H_2%3D4%29%3D0.3125%5Ccdot0.1563%3D0.0488)
First bring like terms together before simplifying
Answer:
The number of years needed is 15.75 years.
Step-by-step explanation:
The investment amount (present value) = $200
Interest rate =4.5%
Double of investment = $400
Now we have to find the time or number of years in which the investment amount will be doubled. So, just use the below formula to find the number of years.
Future value = present value ×(1+interest rate)^n
400 = 200×(1+4.5%)^n
N = 15.75 years
The number of years required to double the amount is 15.75 years.
Answer:
Both the boats will closet together at 2:21:36 pm.
Step-by-step explanation:
Given that - At 2 pm boat 1 leaves dock and heads south and boat 2 heads east towards the dock. Assume the dock is at origin (0,0).
Speed of boat 1 is 20 km/h so the position of boat 1 at any time (0,-20t),
Formula : d=v*t
at 2 pm boat 2 was 15 km due west of the dock because it took the boat 1 hour to reach there at 15 km/h, so the position of boat 2 at that time was (-15,0)
the position of boat 2 is changing towards east, so the position of boat 2 at any time (-15+15t,0)
Formula : D=![\sqrt{(x2-x1)^2+(y2-y1)^2}](https://tex.z-dn.net/?f=%5Csqrt%7B%28x2-x1%29%5E2%2B%28y2-y1%29%5E2%7D)
⇒ ![D = \sqrt{20^2t^2+15(t-1)^2}](https://tex.z-dn.net/?f=D%20%3D%20%5Csqrt%7B20%5E2t%5E2%2B15%28t-1%29%5E2%7D)
Now let ![F(t) = D^2(t)](https://tex.z-dn.net/?f=F%28t%29%20%3D%20D%5E2%28t%29)
∵ ![F'(t) = 800t + 450(t-1) = 1250t -450\\F'(t) =0](https://tex.z-dn.net/?f=F%27%28t%29%20%3D%20800t%20%2B%20450%28t-1%29%20%3D%20%201250t%20-450%5C%5CF%27%28t%29%20%3D0)
⇒ t= 450/1250
⇒ t= .36 hours
⇒ = 21 min 36 sec
Since F"(t)=0,
∴ This time gives us a minimum.
Thus, The two boats will closet together at 2:21:36 pm.