13. There were 120 books on shelf last month, and there are currently 250 books on shelf this month.

NEED HELP NOW PLEASE!!!!

VMariaS [17]

Answer: c = \frac {d + ab} {a}

Step-by-step explanation:

For this case we have the following equation:

a (c - b) = d

We want to solve the equation for the letter c.

To do this, we apply the distributive property:

ac-ab = d

Then, applying addition property of equality we have:

ac = d + ab

Then applying division property of equality we have:

c = \frac {d + ab} {a}

8 0

3 years ago

A student can walk to school in 3/4 of an hour. She can ride to school in 1/6 of that time. What fraction of an hour does it tak

Svetllana [295]

Answer:

1/8 of an hour

Step-by-step explanation:

3/4 x 1/6 = 3/24 = 1/8

Hope this helps!

3 0

3 years ago

Adult tickets to a play cost $22. Tickets for children cost $15. Tickets for a group of 11 people cost a total of $228. Write an

yaroslaw [1]

Adults = 9
Children = 2

Let x be the number of adults.
11-x is the number of children.

22x + 15(11-x) = 228
22x + 165 - 15x = 228
22x - 15x = 228 - 165
7x = 63
7x / 7 = 63 / 7
x = 9 number of adults.

11 - x = 11 - 9 = 2 number of children.

To check:

22x + 15(11-x) = 228
22(9) + 15(11-9) = 228
198 + 30 = 228
228 = 228

7 0

4 years ago

Read 2 more answers

Okay i am begging all of the math wizards on brainly to help me. it is end of the semester for me and im trying so hard not to f

Travka [436]

Answer:

Ok its pretty straight forward

So for every x its 1

And every y its 4/5

To make life simpler lets just make 4/5 into a whole number

So we can make it into 20/5 which equals 4

To get to 20/5 we multiply 4/5 by 5

So we multiply the x by 5 too

We’d get (5,5)

So you can plot that

And the lines should automatically plug in a different point

You can plug it into negatives

-5, -5

so something between those lines

Like i dontt get how lines work here it Make sure its on the 5,5

I can’t think of an equation but I guess

5=m5

In the Format Y=mx (yes no y intercept because its a direct proportion formula)

Or you can use the format

y/x=m

5/5=m

Or if they suggest it in a y intercept formula

y-mx+b

just plug in like y with 5 and the x with 5.

You can also use the plot (10,8) still works :)

If I’m worng I’m sorry the question is weird and I’m assuming they asking you about Proportional/direct relationships

5 0

3 years ago

A public bus company official claims that the mean waiting time for bus number 14 during peak hours is less than 10 minutes. Kar

ch4aika [34]

Answer:

We conclude that the mean waiting time is less than 10 minutes.

Step-by-step explanation:

We are given that a public bus company official claims that the mean waiting time for bus number 14 during peak hours is less than 10 minutes.

Karen took bus number 14 during peak hours on 18 different occasions. Her mean waiting time was 7.8 minutes with a standard deviation of 2.5 minutes.

Let $\mu$ = mean waiting time for bus number 14.

So, Null Hypothesis, $H_0$ : $\mu \geq$ 10 minutes {means that the mean waiting time is more than or equal to 10 minutes}

Alternate Hypothesis, $H_A$ : $\mu$ < 10 minutes {means that the mean waiting time is less than 10 minutes}

The test statistics that would be used here One-sample t test statistics as we don't know about the population standard deviation;

T.S. = $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean waiting time = 7.8 minutes

s = sample standard deviation = 2.5 minutes

n = sample of different occasions = 18

So, test statistics = $\frac{7.8-10}{\frac{2.5}{\sqrt{18} } }$ ~ $t_1_7$

= -3.734

The value of t test statistics is -3.734.

Now, at 0.01 significance level the t table gives critical value of -2.567 for left-tailed test.

Since our test statistic is less than the critical value of t as -3.734 < -2.567, so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region due to which we reject our null hypothesis.

Therefore, we conclude that the mean waiting time is less than 10 minutes.

5 0

4 years ago