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Mathematics

1 answer:

lina2011 [118]3 years ago

8 0

Answer: the last one which is d<0
Trust me :)

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A car travelled 100 km with half the distance at 40 km/h and the other half at 80 km/h. Find the average speed of the car for th

Nana76 [90]

We must look at this question in steps
The first half of the journey is travelled at 40 km/h
Half of 100km is 50 km
Using the formula
Distance = Speed x Time
Speed = Distance / Time
Time = Distance / Speed
We can work out the time:

50km / 40km/h = 1.25 hours

Next we look at the second half of the journey
50km at 80km/h
50km / 80km/h = 0.625 hours

Add together both times to work out how long the entire journey took
1.25 + 0.625 = 1.875 hours

Using the Speed formula from before
Speed = 100km / 1.875 =
53 1/3 km/h or 53.3 recurring km/h

6 0

3 years ago

Find the distance between xequals[Start 2 By 1 Matrix 1st Row 1st Column 8 2nd Row 1st Column negative 5 EndMatrix ]and yequals[

kherson [118]

Answer:

Distance =√(x₁ - y₁)²+ (x₂ - y₂)² = √97 = 9.85

Step-by-step explanation:

The Matrix X and Y could also be referred to as vectors in Rⁿ dimensions.

if Vector X = ( x₁ , x₂) and Vector Y = (y₁ , y₂)

then, Distance (X-Y) = ||X-Y|| = √(x₁ - y₁)²+ (x₂ - y₂)²

where, x₁ = 8, x₂ = -5 and y₁ = -1 , y₂ = -9

Distance = √(8 - (-1))²+ (-5 - (-9))² = √9² + 4² =√97 = 9.85

4 0

3 years ago

A developer wants to enclose a rectangular grassy lot that borders a city street for parking. If the developer has 220 feet of f

MrRa [10]

Answer:

6050 square feet

Step-by-step explanation:

Based on the diagram attached, the area which the available fencing can enclose will measure X x Y feet. As the total length of fencing available is 220 feet, the fenced perimeter must equal 220 feet

$Y + 2X = 220$

$Y = 220 - 2X$

Area of a rectangle is determined by multiplying the length of perpendicular sides:

$Area = X*Y$

$Area = X(220 - 2X)$

$Area = 220X - 2X^{2}$

The derivative of an equation determines the slope at any given point of that equation. At the maximum or minimum point of the equation, the slope will be zero. Therefore, differentiating the equation for area and equating it to zero will give the value of X where the area is maximum.

A simple variable can be differentiated using below concept:

$f(a) = a^{b}$