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3 years ago

Fifteen years later, a man will be two times as old as he was 15 years ago. How old is he now?

Mathematics

2 answers:

Nimfa-mama [501]3 years ago

8 0

Answer:

the man is 45 years.

Step-by-step explanation:

The present age of the man is 45 years. 15 years later : Man will be twice of he was 15 years ago. Therefore the present age of the man is 45 years.

Inga [223]3 years ago

6 0

Answer:

Let the present age of the man be x years.

Age of the man 15 years ago =(x−15) years and

Age of the man 15 years later =(x+15) years

According to the given condition, we have

(x+15)=2(x−15)

⇒x+15=2x−30

⇒x−2x=−30−15

⇒−x=−45 or x=45 years

Hence, the present age of the man is 45 years.

Step-by-step explanation:

Hope it helps you..

Your welcome in advance..

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2 years ago

The pair of variables x=5, y=7 is the solution to the equation ax–2y=1. Find the coefficient a.

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Step-by-step explanation:

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3 years ago

Read 2 more answers

Bill is able to save $35/week after working part-time and paying his expenses. These two formulas show his weekly savings: f(1)

Umnica [9.8K]

1. We use the recursive formula to make the table of values:
f(1) = 35
f(2) = f(1) + f(2-1) = f(1) + f(1) = 35 + 35 = 70
f(3) = f(1) + f(3-1) = f(1) + f(2) = 35 + 70 = 105
f(4) = f(1) + f(4-1) = f(1) + f(3) = 35 + 105 = 140
f(5) = f(1) + f(5-1) = f(1) + f(4) = 35 + 140 = 175

2. We observe that the pattern is that for each increase of n by 1, the value of f(n) increases by 35. The explicit equation would be that f(n) = 35n. This fits with the description that Bill saves up $35 each week, thus meaning that he adds $35 to the previous week's value.

3. Therefore, the value of f(40) = 35*40 = 1400. This is easier than having to calculate each value from f(1) up to f(39) individually. The answer of 1400 means that Bill will have saved up $1400 after 40 weeks.

4. For the sequence of 5, 6, 8, 11, 15, 20, 26, 33, 41...
The first-order differences between each pair of terms is: 1, 2, 3, 4, 5, 6, 7, 8...since these differences form a linear equation, this sequence can be expressed as a quadratic equation. Since quadratics are functions (they do not have repeating values of the x-coordinate), therefore, this sequence can also be considered a function.

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4 years ago

A company produces a cardboard box in the shape of a rectangular prism. The surface area of the box is represented by S=10x2, wh

OLEGan [10]

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3 years ago

Evaluate the triple integral ∭ExydV where E is the solid tetrahedon with vertices (0,0,0),(5,0,0),(0,9,0),(0,0,4).

Elan Coil [88]

Answer: $\int\limits^a_E {\int\limits^a_E {\int\limits^a_E {xy} } \, dV$ = 1087.5

Step-by-step explanation: To evaluate the triple integral, first an equation of a plane is needed, since the tetrahedon is a geometric form that occupies a 3 dimensional plane. The region of the integral is in the attachment.

An equation of a plane is found with a point and a normal vector. Normal vector is a perpendicular vector on the plane.

Given the points, determine the vectors:

P = (5,0,0); Q = (0,9,0); R = (0,0,4)

vector PQ = (5,0,0) - (0,9,0) = (5,-9,0)

vector QR = (0,9,0) - (0,0,4) = (0,9,-4)

Knowing that cross product of two vectors will be perpendicular to these vectors, you can use the cross product as normal vector:

n = PQ × QR = $\left[\begin{array}{ccc}i&j&k\\5&-9&0\\0&9&-4\end{array}\right]$ $\left[\begin{array}{ccc}i&j\\5&-9\\0&9\end{array}\right]$