An expression is Show : 6x(4+2x4)+10 what is the value of the expression

There were 100 questions on a math test. If Jamal got 4 times as many right as he got wrong, what was Jamals score?

IgorLugansk [536]

Jamal's score is 80

<u>Explanation:</u>

Given:

Number of questions = 100

Let w be the number of wrong answers

Let r be the number of right answers

According to question,

r = 4w

r + w = 100

Solving both the equations we get:

4w + w = 100

5w = 100

w = 20

If w = 20 then r = 4 X 20 = 80

Therefore, Jamal's score is 80

7 0

3 years ago

A company has 8 mechanics and 6 electricians. If an employee is selected at random, what is the probability that they are an ele

Andre45 [30]

Answer:

$Probability = \frac{3}{7}$

Step-by-step explanation:

Given

Electrician = 6

Mechanic = 8

Required

Determine the probability of selecting an electrician

First, we need the total number of employees;

$Total = n(Electrician) + n(Mechanic)$

$Total = 6 + 8$

$Total = 14$

Next, is to determine the required probability using the following formula;

$Probability = \frac{n(Electrician)}{Total}$

$Probability = \frac{6}{14}$

Divide numerator and denominator by 2

$Probability = \frac{3}{7}$

<em>Hence, the probability of selecting an electrician is 3/7</em>

4 0

3 years ago

Expansion Numerically Impractical. Show that the computation of an nth-order determinant by expansion involves multiplications,

posledela

Answer:

number of multiplies is n!
n=10, 3.6 ms
n=15, 21.8 min
n=20, 77.09 yr
n=25, 4.9×10^8 yr

Step-by-step explanation:

Expansion of a 2×2 determinant requires 2 multiplications. Expansion of an n×n determinant multiplies each of the n elements of a row or column by its (n-1)×(n-1) cofactor determinant. Then the number of multiplies is ...

mpy[n] = n·mp[n-1]

mpy[2] = 2

So, ...

mpy[n] = n! . . . n ≥ 2

__

If each multiplication takes 1 nanosecond, then a 10×10 matrix requires ...

10! × 10^-9 s ≈ 0.0036288 s ≈ 0.004 s . . . for 10×10

Then the larger matrices take ...

n=15, 15! × 10^-9 ≈ 1307.67 s ≈ 21.8 min

n=20, 20! × 10^-9 ≈ 2.4329×10^9 s ≈ 77.09 years

n=25, 25! × 10^-9 ≈ 1.55112×10^16 s ≈ 4.915×10^8 years

_____

For the shorter time periods (less than 100 years), we use 365.25 days per year.

For the longer time periods (more than 400 years), we use 365.2425 days per year.

8 0

3 years ago

Paisley's car used 11 gallons to travel 374 miles. How many gallons of gas would she need to travel 442 miles?

katen-ka-za [31]

Answer:

13 gallons

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers

A grain silo has the shape of a right circular cylinder surmounted by a hemisphere. If the silo is to have a volume of 505π ft3,

Romashka-Z-Leto [24]

Answer:

radius x = 3 ft

height h = 23,8 ft

Step-by-step explanation:

From problem statement

V(t) = V(cylinder) + V(hemisphere)

let x be radius of base of cylinder (at the same time radius of the hemisphere)

and h the height of the cylinder, then:

V(c) = π*x²*h area of cylinder = area of base + lateral area

A(c) = π*x² + 2*π*x*h

V(h) = (2/3)*π*x³ area of hemisphere A(h) = (2/3)*π*x²

A(t) = π*x² + 2*π*x*h + (2/3)*π*x²

Now A as fuction of x

total volume 505 = π*x²*h + (2/3)*π*x³

h = [505 - (2/3)* π*x³ ] /2* π*x

Now we have the expression for A as function of x

A(x) = 3π*x² + 2π*x*h A(x) = 3π*x² + 505 - (2/3)π*x³

Taking derivatives both sides

A´(x) = 6πx - 2πx² A´(x) = 0 6x - 2x² = 0

x₁ = 0 we dismiss

6 - 2x = 0

x = 3 and h = [505 - (2/3)* π*x³]/2* π*x

h = (505 - 18.84) / 6.28*3

h = 23,8 ft

7 0

3 years ago