Question 1:

$5, $10

Question 2:

33, 44

Question 3:

84kg, 36kg

Question 4:

$18, $36

Question 5:

$12, $20

Question 6:

$84 (Since 7 is the greater part of the ratio, we only need to look up 7 on the slide rule.)

Question 7:

$18, $27, $54

This questions seems a bit awkward to handle on the slide rule, doesn't it.  There doesn't appear to be any way we can align, 99 and 11.  Why not?  The reason for this is that in some questions, the ratio is not in its lowest form.  You might be able to see that 99 over 11 can be simplified to 9 over 1, but how can we check this?  Let's ask our friend, the CI scale!  Line up D99 with C10 (the right index C1) and then move the cursor to CI11.  On the D scale, we can now read D9.  So our next step is to line up C10 (the right index C1) with D9 and then read off our answers.

Question 8:

(a) $3000 (b) $2000 (=$5000-$3000)

No this isn't a trick question! Because the sum of the parts is 12 (3+4+5) and the amount is $12,000, the C and D scales will line up with each other.  So in this case it is very easy to read the values.

Be careful here, the question asks how much more the largest value is, not what the largest value is.

Question 9:

2100

Ah ... using the CI scale again to simplify the ratio!

Now move the right index to D3 and read the results.

Since we are only asked for the number of children, we only need to look up the 7 on the slide rule.