Answer:
Step-by-step explanation:
let s be speed and t be time taken
s*t=649
(s+8)(t-4)=649
st-4s+8t-32=649
-4s+8t-32=0
4s=8t-32
s=2t-8
2t=s+8
t=4+s/2
![s*(\frac{s}{2}+4)=649\\s^2+8s=649\\s^2+8s-649=0\\find s](https://tex.z-dn.net/?f=s%2A%28%5Cfrac%7Bs%7D%7B2%7D%2B4%29%3D649%5C%5Cs%5E2%2B8s%3D649%5C%5Cs%5E2%2B8s-649%3D0%5C%5Cfind%20s)
Answer:
the answer is C
Step-by-step explanation:
Answer:
8/15 cups of flour
Step-by-step explanation:
Divide the 47 teaspoons of baking powder she has by the number necessary to make bread:
47 teaspoons/ 16 teaspoons = 2 possible loaves of bread
Same for the flour:
15 cups/4 cups = 3 possible loaves
Since we don't have enough baking soda to make three loaves, we have enough supplies to make two full loaves.
so to figure out the fraction we need 8 cups of flour divided by 15 cups of flour:
8/15 cups of flour
You add each side together or do length+width x 2
Answer:
a) the sample size (n) = 156.25≅ 156
Step-by-step explanation:
<u>Step1 </u>:-
Given the two sample sizes are equal so ![n_{1} =n_{2} = n](https://tex.z-dn.net/?f=n_%7B1%7D%20%3Dn_%7B2%7D%20%3D%20n)
Given the standard error (S.E) = 0.04
The standard error of the proportion of the given sample size
![S.E = \sqrt{\frac{pq}{n} }](https://tex.z-dn.net/?f=S.E%20%3D%20%5Csqrt%7B%5Cfrac%7Bpq%7D%7Bn%7D%20%7D)
Step 2:-
here we assume that the proportion of boys and girls are equally likely
p= 1/2 and q= 1/2
![S.E = \sqrt{\frac{p(1-p)}{n} } \leq \frac{\frac{1}{2} }{\sqrt{n} }](https://tex.z-dn.net/?f=S.E%20%3D%20%5Csqrt%7B%5Cfrac%7Bp%281-p%29%7D%7Bn%7D%20%7D%20%5Cleq%20%5Cfrac%7B%5Cfrac%7B1%7D%7B2%7D%20%7D%7B%5Csqrt%7Bn%7D%20%7D)
![\sqrt{n} = \frac{\frac{1}{2} }{S.E}](https://tex.z-dn.net/?f=%5Csqrt%7Bn%7D%20%3D%20%5Cfrac%7B%5Cfrac%7B1%7D%7B2%7D%20%7D%7BS.E%7D)
squaring on both sides, we get
![n = \frac{1}{(2X0.04)^{2} }](https://tex.z-dn.net/?f=n%20%3D%20%5Cfrac%7B1%7D%7B%282X0.04%29%5E%7B2%7D%20%7D)
on simplification, we get
n= 156.25 ≅ 156
sample size (n) = 156
<u>verification</u>:-
Standard error = 0.04