Answer:
Omar spent $100 to earn 600 reward points.
Explanation:
The reward points are proportional to the money spent.
Thus, we can determine the amount of money Omar spent to earn 600 reward points by creating two proportions where a refers to the amount of money spent:
1800 reward points / $300 spent = 600 reward points / $a spent
1800/300 = 600/a
(6 = 600/a) * a
(6a = 600) / 6
a = 100
Thus, Omar spent $100 to earn 600 reward points.