Good Afternoon,
I will go over each one so you understand:
First Question: How far can snail D travel in 1 hour?
Well, we know That snail D travels 6 inches in 30 minutes, and we also know that 30 minutes is
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of an hour. Therefore, we can multiply 30 minutes by 2 to get an hour, and do the same with the amount of inches this snail travels. So 6 x 2 = 12. He travels 12 inches in an hour :)
Second Question: Here we do the same thing, except the snail travels 1 inch in 15 minutes and we want to know how much he travels in 30 minutes, so 2 x 1 = 2. The snail travels 2 inches in 30 minutes. Thats a slow snail!