Answer:
9 weeks
Explanation:
Divide the total pairs of shoes by how many you lose in a week and it will give you about how many weeks it'll take to get rid of all of the shoes:
35 / 3 = 11.67
Knowing your multiplication table is key for this! You will know that the best answer for this is 9 (and not 8 or 10) because...
3 x 8 = 24
3 x 9 = 27
3 x 10 = 30
Which will give you less than 10 pairs:
35 - 27 = 8