Middle School

In which of the tables are x and y inversely proportional?

A.
x = 1, 2, 3, 4
y = 6, 3, 2, 1.5

B.
x = 2, 3, 5, 7
y = 7.5, 5, 3, 2

C.
x = 1, 3, 4, 24
y = 24, 8, 6, 1

D.
x = 0.1, 0.3, 25, 100
y = 200, 40, 0.8, 0.2

Answer :

Answer:

A, C

Step-by-step explanation:

If it is inversely proportional then y = k/x

Let's try one by one for the options. (im replacing y and x in the equation and finding k to see if k is the same all throughout)

A.

6 = k/1 (k=6)

3 = k/2 (k=6)

2 = k/3 (k=6)

1.5 = k/4 (k=6)

Yes! It's the same everywhere so this is correct!

B.

7.5 = k/2 (k=15)

5 = k/3 (k=15)

3 = k/5 (k=15)

2 = k/7 (k=14)

For the last one k is not the same so nope. It is wrong.

C.

24 = k/1 (k=24)

8 = k/3 (k=24)

k = 6×4 = 24

k = 24×1 = 24

This is correct too.

D.

k = 0.1×200 = 20

k = 0.3×40 = 12

k = 0.8 × 25 = 20

We can already see that k is not the same everywhere.

Only A and C, x and y are inversely proportional for all of the values

Answer: c

Step-by-step explanation: