Answer:
13.5 = 9.5 + x
x=4
Step-by-step explanation:
In this problem, the price of the baseball cap, which is $9.50, and a baseball, whose price is unknown (and therefore must be the variable), total $13.50. So, to set up the equation add the two prices and set them equal to the total, 9.5+x=13.5.
Then, using the subtraction property of equality subtract 9.5 from both sides. This means x=4, so the baseball cost 4 dollars.
Answer:
A loss of weight means we subtract from Jack's current weight.
Step-by-step explanation:
A loss of weight means we subtract from Jack's current weight. New Weight = Current Weight - Weight Loss per week * number of weeksNew Weight =257 - 3*12New Weight =257 - 36New Weight = 221
Answer:
9 4/7
Step-by-step explanation:
First, we need to make as many 7s as possible. If we do 67/7, we will get 9...... so our whole number is 9. If we do 7 x 9, we get 63 and if we subtract 63 from 67, we are left with 4. All in all, we will get 9 4/7!
Answer:
angle D = 54°
Step-by-step explanation:
Supplementary angles sum to 180°
To calculate D, subtract angle C from 180
angle D = 180° - 126° = 54°
Answer:
a) E(X) = 71
b) V(X) = 20.59
Sigma = 4.538
Step-by-step explanation:
<em>The question is incomplete:</em>
<em>According to a 2010 study conducted by the Toronto-based social media analytics firm Sysomos, 71% of all tweets get no reaction. That is, these are tweets that are not replied to or retweeted (Sysomos website, January 5, 2015).
</em>
<em>
Suppose we randomly select 100 tweets.
</em>
<em>a) What is the expected number of these tweets with no reaction?
</em>
<em>b) What are the variance and standard deviation for the number of these tweets with no reaction?</em>
This can be modeled with the binomial distribution, with sample size n=100 and p=0.71, as the probability of no reaction for each individual tweet.
The expected number of these tweets with no reaction can be calcualted as the mean of the binomial random variable with these parameters:

The variance for the number of these tweets with no reaction can be calculated as the variance of the binomial distribution:

Then, the standard deviation becomes:
