Who is asking: Student

Level: Middle

Question:

In the ratio 3:8=17__, can__be a whole number? Explain your answer.

Hi,
Look at two ratios that are equal like

3:5 = 6:10
I know they are equal since 6 is 2 times 3, and 10 is 2 times 5. That is each part of the ratio on the right is the same multiple of the corresponding part on the left.
Another example is

27:15= 9:5
Here 9 is ^{1}/_{3} times 27, and 5 is ^{1}/_{3} times 15.
In your example 17 is ^{17}/_{3} times 3 so the second part of the ration on the right is ^{17}/_{3} times 8 which is not a whole number.

Penny