Algebra 1

Direct Variation

Try the following:
1.

If m varies directly as y and m is 6 when y is 36, find the Choose: constant of variation.
1/6
6
1/36
36
Explanation

2.

"a varies directly as b". If a = 3 when b = 24, find b when a = 10.

Choose:
1.25
8
36
80

Explanation

3.

There are about 200 calories in 50 grams of Swiss cheese. Choose:
Willie ate 70 grams of this cheese. About how many
210
calories were in the cheese that he ate if the number of
240
calories varies directly as the weight of the cheese.
280
290

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Explanation

4.

In the following chart, does one variable vary directly with Choose: the other?
Yes
M
3
4
5
6
7
No
N
6
8
10
12
14
Explanation

5.

In the following chart, does one variable vary directly with Choose: the other?
Yes
X
1
2
3
4
5
No
Y
1
4
9
12
15
Explanation

6. One variable (A) varies directly as the other (C).

Find the missing numbers x and y. Write the formula which relates the variables.
A
C

1
3

2 y x
15

Choose: x = 3 and y = 6 x = 13 and y = 4 x = 5 and y = 6 x = 4 and y = 9

Explanation

7.

The resistance (R) of a copper wire, varies directly as its length (L). Write this relation as a formula using k as the constant of variation.

Explanation

Direct Variation

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8.

A salesman's commission varies directly as his sales. Write Choose: the formula relating this situation and denote the variables.
$125
If the commission is $100 for $1000 in sales, find the
$150
commission for $1750 in sales.
$175
$200
Explanation

9.

The distance an object, a, drops from rest in freefall varies Choose: directly with the square of the time, t. If a varies directly as
6
t2, and a = 12 when t = 2, find a when t = 3.
9
27
81
Explanation

10.

Which equation represents: x varies directly as y, and x = 12 when y = 36?

Choose:

Explanation

11.

Which graph represents a