All categories

3 years ago

5 pen cost 20. find the cost of 8 pens and then 15 pens

Mathematics

1 answer:

Anna007 [38]3 years ago

3 0

Answer:

8 pen : 26

15 pen : 60

Step-by-step explanation:

5 pen = 20

Times both sides by 2

10 pen = 40

add 5 pen = 20

15 pen = 60

Divide 10 by 5

2 pen = 4

1 pen = 2

Add them together

3 pen = 6

Add 5 pens and 20

8 pen = 26

You might be interested in

The graph h = −16t^2 + 25t + 5 models the height and time of a ball that was thrown off of a building where h is the height in f

Thepotemich [5.8K]

Answer:

part 1) 0.78 seconds

part 2) 1.74 seconds

Step-by-step explanation:

step 1

At about what time did the ball reach the maximum?

Let

h ----> the height of a ball in feet

t ---> the time in seconds

we have

$h(t)=-16t^{2}+25t+5$

This is a vertical parabola open downward (the leading coefficient is negative)

The vertex represent a maximum

The x-coordinate of the vertex represent the time when the ball reach the maximum

Find the vertex

Convert the equation in vertex form

Factor -16

$h(t)=-16(t^{2}-\frac{25}{16}t)+5$

Complete the square

$h(t)=-16(t^{2}-\frac{25}{16}t+\frac{625}{1,024})+5+\frac{625}{64}$

$h(t)=-16(t^{2}-\frac{25}{16}t+\frac{625}{1,024})+\frac{945}{64}\\h(t)=-16(t^{2}-\frac{25}{16}t+\frac{625}{1,024})+\frac{945}{64}$

Rewrite as perfect squares

$h(t)=-16(t-\frac{25}{32})^{2}+\frac{945}{64}$

The vertex is the point $(\frac{25}{32},\frac{945}{64})$

therefore

The time when the ball reach the maximum is 25/32 sec or 0.78 sec

step 2

At about what time did the ball reach the minimum?

we know that

The ball reach the minimum when the the ball reach the ground (h=0)

For h=0

$0=-16(t-\frac{25}{32})^{2}+\frac{945}{64}$

$16(t-\frac{25}{32})^{2}=\frac{945}{64}$

$(t-\frac{25}{32})^{2}=\frac{945}{1,024}$

square root both sides

$(t-\frac{25}{32})=\pm\frac{\sqrt{945}}{32}$

$t=\pm\frac{\sqrt{945}}{32}+\frac{25}{32}$

the positive value is

$t=\frac{\sqrt{945}}{32}+\frac{25}{32}=1.74\ sec$

8 0

3 years ago

LAST TIME can someone explain how YOU FOUND OUT TAIWAN HAS 928 CASES, PLEASE HELP ME

polet [3.4K]

Answer:

you minus them

Step-by-step explanation:

3 0

3 years ago

Brian was scuba diving at the Great Barrier Reef in Australia. After he jumped in the water, he descended 18 feet. Then he rose

Levart [38]

amswer:

-13 feet

step by step:

-18+5=-13

8 0

3 years ago

A company made $785 in a ticket sale they sold 100 tickets how much did the company make per ticket if each ticket cost the same

zubka84 [21]

They made 7.85 per ticket

4 0

3 years ago

Find the area of the shaded region.

yaroslaw [1]

It’s ether 138.6 or 101.4. 123 rounded to the nearest tenth is 120 so you ether add or subtract

4 0

3 years ago

5 pen cost 20. find the cost of 8 pens and then 15 pens​

5 pen cost 20. find the cost of 8 pens and then 15 pens