Omar spent 600 dollars for earning 1800 reward points.
<em><u>Explanation</u></em>
Omar earns 300 reward points for every 100 dollars he spends.
Suppose, he spent
dollar for 1800 reward points.
Now <u>according to the ratio of "amount of money spent" and "reward points"</u> , the equation will be......

Thus, Omar spent 600 dollars for earning 1800 reward points.
They each get half a slice of pizza
It’s b , i hope it’s not wrong :)