12 months in a year. So 18 months= 1 year and 6 months. Izzys dog is 10 1/2= 10 years and six months. Then subtract 1 year and 6 months by 10 year and six months and it would be exactly 9 years older.
You would solve it just like how you would solve it with numbers.Solve it like how you would solve this 7=6*2.
First, change 2/5 into a decimal by dividing 2 by 5. Decimal= .4. Now move the decimal 2 places to the right to find percentage. Answer is 40%
This is given by the multinomial coefficient:

If you're not familiar with the multinomial coefficient, you may be able to see it more clearly if you count the number of possible combinations taking each distinct letter

times, where

is the number of times it shows up in the original word.
The first one is 3 8/10 are not rotten because 5 3/10- 1 5/10 = 3 8/10
The second one needs information on the strawberries which it dosen't show on the picture.
Hope this helped a bit.