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3 years ago

On a map, 1 cm represents 30 km. Two cities on the map are 2.3 cm apart.

Mathematics

1 answer:

Lorico [155]3 years ago

8 0

Answer:

D. 69 Km

Step-by-step explanation:

Scaling

Maps usually represent real areas on the field, but since they cannot fit in pieces of paper, we use scales where sizes and distances are all proportional to the real measurements.

On the map of the question, we know 1 cm represents 30 Km. It means that we can know approximate real distances by measuring the distances on the paper or blueprints.

Two cities are 2.3 cm apart on the map, it means that they are really 2.3*30 =69 Km apart

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Answer: y = -2x + 7

Step-by-step explanation:

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3 years ago

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Write an expression to represent . Eight less than the product of two and a number x

kvv77 [185]

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3 years ago

Calls from a call box are charged per minute at one rate for the five minutes, then a different rate for each additional minute.

nirvana33 [79]

Answer:

c. $0.75 per minute at one rate for the first 5 minutes and $0.25 per minute thereafter

Step-by-step explanation:

The last 5 minutes of the 12-minute call cost ...

$5.50 -4.25 = $1.25

so the per-minute rate at that time is ...

$1.25/(5 min) = $0.25/min . . . . . . . . matches choice C only

You know the answer at this point, but if you want to check the rate for the first 5 minutes, you can subtract 2 minutes from the 7-minute call to find that ...

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3 years ago

Find the sum of the first 20 terms of the arithmetic sequence 4, -4, -12, -20

Vsevolod [243]

Answer:

The sum of the first 20 terms is -1440.

Step-by-step explanation:

We want to find the sum of the first 20 terms of the arithmetic sequence:

4, -4, -12, -20...

The sum of an arithmetic sequence is given by:

$\displaystyle S=\frac{k}{2}(a+x_k)$

Where k is the number of terms, a is the initial term, and x_k is the last term.

Since we want to find the sum of the first 20 terms, k = 20.

Our initial term a is 4.

Our last term is also the 20th term as we want the sum of the first 20 terms.

To find the 20th term, we can write an explicit formula for our sequence. The explicit formula for an arithmetic sequence is given by:

$x_n=a+d(n-1)$

Where a is the initial term, d is the common difference, and n is the nth term.

Our initial term is 4. From the sequence, we can see that our common difference is -8 since each subsequent term is eight less than the previous term. Therefore:

$x_n=4-8(n-1)$