Answered

Three friends bought 4, 6, and 8 books. The table shows the cost of the books.


Number of Books 4 6 8

Cost ($) 30 45 60

What is the constant of proportionality?

A2

B.7.5


C.15


D.30

Verified Answer :

Answer:

Option (B) is correct .

The constant of proportionality is 7.5 .

Reason

Let us assume that the number of books be x.

Let us assume that the cost of books be y .

Than

\(y \propto x\)

y = kx

Where k is constant of proportionality .

As given

Number of Books 4 6 8

Cost ($) 30 45 60

Thus

when x = 4 , y = 30

Put in the equation y = kx .

\(30 = 4k\)

\(k = \frac{30}{4}\)

k = 7.5

when x = 6 , y = 45

Put in the equation y = kx .

\(45 = 6k\)

\(k = \frac{45}{6}\)

k = 7.5

when x = 8 , y = 60

Put in the equation y = kx .

\(60 = 8k\)

\(k = \frac{60}{8}\)

k = 7.5

Therefore the constant of proportionality is 7.5  i.e option (B) is correct .

Answer:

B.

Step-by-step explanation:

I took the K12 test so the answer above is correct

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