Answer:
How far should he ride on each of the four days to reach his goal?
1st day:
miles
2nd day:
miles
3rd day:
miles
4th day:
miles
Explanation: As the problem says,
is the number of miles he rides on the first day. Let's start off with that.
1st day:
miles
He want to ride 1.5 times as far as he rode the day before... no 1.5 more, but 1.5 times as far as he rode the day before; you would multiply 1.5 with the previous day's length.
2nd day:

Then you multiply
to
to get the third day's.
3rd day:

4th day:

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Phew! Gavin wants to ride a total of 65 miles over these four days, so if Gavin added all the miles of the four days, he should get 65...
1st+2nd+3rd+4th=65




Yes! Now that we've got the hard part done... substitute 8 for ever single
.
1st day:
miles
2nd day:
miles
3rd day:
miles
4th day:
miles
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Checking my answer:
Just add the miles!


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Hope that helps! :D