Let Mary's age be x.
Paul is three times as old as Mary, so Paul's age would be 3x.
Peter is four times as old as Mary, so Peter's age would be 4x.
The sum of their ages is 64
⇒ Paul's age+ Peter's age+ Mary's age= 64
⇒ 3x+ 4x+ x= 64
⇒ 8x= 64
⇒ x= 64/8
⇒ x= 8
Paul's age is: 3x= 3*8= 24
Peter's age is: 4x= 4*8= 32
Final answer: Paul is 24 years old.
Peter is 32 years old.
Mary is 8 years old.
Hope this helps~
Answer:
1.43%
Step-by-step explanation:
we have that we can solve it by means of binomial, in this case m = 25. Also the probability of head is 50%. we need to know when it falls 7 times, therefore x = 7
the formula is:
P (x) = mCx * p ^ x * q ^ (m-x)
we know that p is 0.5 therefore q is equal to 0.5, replacing:
P (7) = 25C7 * 0.5 ^ 7 * 0.5 ^ (25-7)
P (7) = 25! / (7! * (25-7)!) * 0.5 ^ 7 * 0.5 ^ (25-7)
P = 0.0143
that is, the probability is 1.43%
X1=radical 6--->2.44
X2=-radical 6/3--->-0.816
I'll explain how to do the first one:-
y = cos-1(x2)
This can be described as ' a function of a function' x^2 is a function of x and cos-1(x^2) is a function of x^2.
We need to apply the chain rule.
Personally I find this easier to understand if i let u = x^2, so
If y = f(u) and u is a function of x then
dy/dx = dy/ du * du/dx
Here u = x^2 and y = cos-1(u)
du/dx = 2x
so dy/dx = d(cos-1(x^2) dx = dy/du * du/dx
= -1 / √(1 - u^2) * 2x
= -2x / √(1 - u^2)
= -2x / √(1 - (x^2)^2)
= -2x / √(1 - x^4)
I hope this helps. but if not. you might like to employ the formulae in the question - The square boxes contain the 'u' s in my answer. These formulae are equivalent to my explanation.
Answer:
1. X > 8
2. a. X < 5
Step-by-step explanation:
1. 3x - 8 > 16
+8. +8
3x > 24
divide both sides by 3
x >8
2. 2x - 1 < 9
+1. +1
2x < 10
divide both sides by 2
x < 5
