Interactive practice questions
Consider the values in each table. Which of them could represent a directly proportional relationship between $x$x and $y$y?
| $x$x | $1$1 | $3$3 | $5$5 | $7$7 |
|---|---|---|---|---|
| $y$y | $50$50 | $40$40 | $30$30 | $20$20 |
A
| $x$x | $1$1 | $2$2 | $3$3 | $4$4 |
|---|---|---|---|---|
| $y$y | $5$5 | $20$20 | $45$45 | $80$80 |
B
| $x$x | $1$1 | $2$2 | $3$3 | $4$4 |
|---|---|---|---|---|
| $y$y | $5$5 | $10$10 | $15$15 | $20$20 |
C
| $x$x | $1$1 | $5$5 | $6$6 | $20$20 |
|---|---|---|---|---|
| $y$y | $100$100 | $75$75 | $50$50 | $25$25 |
D
Easy
< 1min
Which of the following is the best description of direct proportion?
Easy
< 1min
$a$a is directly proportional to $b$b and $a=60$a=60 when $b=6$b=6.
Easy
2min
Which two graphs indicate that $y$y is directly proportional to $x$x?
Easy
< 1min
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