Question

Martin can run 1 mile in 7 minutes. What proportions can be written from this information?

Answer 1

Answer:

$\frac{1}{7}=\frac{3}{21}$

$\frac{7}{1}=\frac{21}{3}$

Step-by-step explanation:

Verify each case

case 1) $\frac{1}{7}=\frac{3}{21}$

Multiply in cross and then compare both sides

$1*21=7*3$

$21=21$ ----> is true

therefore

Is a valid proportion

case 2) $\frac{1}{21}=\frac{3}{7}$

Multiply in cross and then compare both sides

$7*1=21*3$

$7=63$ ----> is not true

therefore

Is not a valid proportion

case 3) $\frac{7}{1}=\frac{3}{21}$

Multiply in cross and then compare both sides

$21*7=1*3$

$147=3$ ----> is not true

therefore

Is not a valid proportion

case 4) $\frac{7}{1}=\frac{21}{3}$

Multiply in cross and then compare both sides

$3*7=1*21$

$21=21$ ----> is true

therefore

Is a valid proportion

case 5) $\frac{1}{7}=\frac{21}{3}$

Multiply in cross and then compare both sides

$3*1=7*21$

$3=147$ ----> is not true

therefore

Is not a valid proportion

Answer 2

Answer:

a and d

Step-by-step explanation: