Answer: 270
Explanation:
Given: For every three texts you send you get 20 points.
Let x be the number of text need to send to score 1800 points.
Also the number of points is directly proportional to the number of texts,
Therefore,
![(3)/(20)=(x)/(1800)\\\Rightarrow\ x=(1800*3)/(20)\\\Rightarrow\ x=270](https://img.qammunity.org/2020/formulas/mathematics/high-school/cvmmzmh1g6rw2kn9mhfwcm1bdaamdsa8er.png)
Hence, we need to send 270 texts to get the prize.