Ask question

Ask question

All categories

3 years ago

5

Dina and Masha started out on a 10 km bike path at the same time. When Dina reached the end of the 10 km, Masha still had 2 km l

eft to bike. If Dina’s biking speed was 5 km/h, find Masha’s biking speed.

2 answers:

labwork [276]3 years ago

6 0

4 km/h because 10-2 because of the 2 km left which =8 then you divide that by 2 to figure out the km per hour which = 4 so 4 km/h

Alex3 years ago

5 0

Answer:

4 km/hr

Step-by-step explanation:

Dina and Masha started out on a 10 km bike path at the same time.

Distance = 10 km

Dina’s biking speed was 5 km/h

Time taken by Dina is Distance / speed

So $time (Dina) = \frac{10}{5} =2$

Time taken by Dina is 2 hours

Same time is taken by Masha but 2 km left

So distance covered by Masha in 2 hours is 10-2 = 8 km

We know speed = distance / time

$speed of Masha = \frac{8}{2}=4$

Masha’s biking speed= 4km/hr

You might be interested in

What is the rate of change for the function (1,15) and (3,45)

Tresset [83]

Answer:

the rate of change is 15

Step-by-step explanation:

(1, 15)

(3, 45)

now we need to find 2

if the rate is 15, 2 should be 30

1, 15

+1, +15

2, 30

+1, +15

3, 45

the rate of change is 15

7 0

3 years ago

What is the solution to this system of linear equations 2x+y=1 and 3x-y=-6

nikklg [1K]

2x + y = 1
3x - y = -6
---------------add
5x = -5
x = -5/5
x = -1

2(-1) + y = 1
-2 + y = 1
y = 1 + 2
y = 3

solution is (-1,3)

8 0

3 years ago

A man's age is three years less than 4 times the age of his oldest daughter. What is age of his daughter

miskamm [114]

A=4×-3 I think this is the equation

4 0

4 years ago

A rectangular field with one side along a river is to be fenced. Suppose that no fence is needed along the river, the fence on t

Andreas93 [3]

Answer:

a) Side Parallel to the river: 200 ft

b) Each of the other sides: 400 ft

Step-by-step explanation:

Let L represent side parallel to the river and W represent width of fence.

The required fencing (F) would be $F=L+2W$ .

We have been given that field must contain 80,000 square feet. This means area of field must be equal to 80,000.

$LW=80,000...(1)$

We are told that the fence on the side opposite the river costs $20 per foot, and the fence on the other sides costs $5 per foot, so total cost (C) of fencing would be $C=20L+5(2W)\Rightarrow 20L+10W$ .

From equation (1), we will get:

$L=\frac{80,000}{W}$

Upon substituting this value in cost equation, we will get:

$C=20(\frac{80,000}{W})+10W$

$C=\frac{1600,000}{W}+10W$

$C=1600,000W^{-1}+10W$

To minimize the cost, we need to find critical points of the the derivative of cost function as:

$C'=-1600,000W^{-2}+10$

$-1600,000W^{-2}+10=0$

$-1600,000W^{-2}=-10$

$-\frac{1600,000}{W^2}=-10$

$-10W^2=-1,600,000$

$W^2=160,000$

$\sqrt{W^2}=\pm\sqrt{160,000}$

$W=\pm 400$

Since width cannot be negative, therefore, the width of the fencing would be 400 feet.

Now, we will find the 2nd derivative as:

$C''=-2(-1600,000)W^{-3}$

$C''=3200,000W^{-3}$

$C''=\frac{3200,000}{W^3}$

Now, we will substitute $W=400$ in 2nd derivative as:

$C''(400)=\frac{3200,000}{400^3}=\frac{3200,000}{64000000}=0.05$

Since 2nd derivative is positive at $W=400$ , therefore, width of 400 ft of the fencing will minimize the cost.

Upon substituting $W=400$ in $L=\frac{80,000}{W}$ , we will get:

$L=\frac{80,000}{400}\\\\L=200$

Therefore, the side parallel to the river will be 200 feet.

4 0

3 years ago

The oblique pyramid has a square base. What is the volume of the pyramid? 2.5 cm3 5 cm3 6 cm3 7.5 cm3

Olenka [21]

Take a look at the attachment below. It fills in for the attachment that wasn't provided in the question -

An oblique pyramid is one that has a top not aligned with the base. Due to this, the height of the pyramid connects with two vertices at its ends to form a right angle present outside the pyramid, knowing that it is always perpendicular to the base. There is no difference between the calculations of the volume of an oblique pyramid and a pyramid however -

$\\Base Area = 2 cm * 2 cm = 4 cm^2,\\Volume ( Pyramid ) = 1 / 3 * ( Base Area ) * ( Height ),\\Volume = 1 / 3 * ( 4 ) * ( 3.75 ),\\-------------------------\\Volume = 5 cm^3$

<u><em>And thus, you're solution is 5 cm^3, or in other words option b!</em></u>

3 0

3 years ago