AMC Upper Primary 2009 Q25

Question 25 

Solutions: 

Step 1: Get the information from question

Step 2: Get the conditions for this question

Step 3: Guess the possible combination of pets for Thomas

Step 4: It is definitely no. fish of Thomas = no. dog of Susie

no.dog of Susie = no. dog of Thomas +3

So, 

no. fish of Susie = no. dog of Thomas +3

Step 5: There is only two possible combination of pets for Thomas.
Find the number of pets for Susie, based on the number of Thomas.

Step 6: Get the answer

Please refer to the link 2019-UpperPrimary-Q25

Question 2019-UpperPrimary-Question