Proportions

Advanced Math 7 · Unit 14 · direct-inverse-proportion

direct-inverse-proportion

Name ______________________________Date ______________

1.
$y$ is directly proportional to $x$ , and $y = 12$ when $x = 4$ . Find $y$ when $x = 7$ .
Answer: ______________
2.
The table shows pairs of values of $x$ and $y$ . Decide whether $y$ is directly or inversely proportional to $x$ , then find the missing value.

$x$ $2$ $4$ $10$
$y$ $30$ $15$ $?$

Enter the missing value of $y$ .
Answer: ______________
3.
A spring stretches $6$ cm when a $1.5$ kg mass hangs from it and $14$ cm when a $3.5$ kg mass hangs from it. The stretch $y$ (in cm) is directly proportional to the mass $x$ (in kg). Write the rule for $y$ in terms of $x$ .
Answer: ______________
4.
It takes $6$ painters $10$ days to paint a fence. Working at the same rate, how many days would it take $12$ painters?
1. (A)
  $2.5$ days
2. (B)
  $5$ days
3. (C)
  $20$ days
4. (D)
  $60$ days
5.
$a$ is directly proportional to $b$ , and $b$ is inversely proportional to $c$ . When $c = 4$ , $a = 6$ . What is $a$ when $c = 12$ ?
Answer: ______________