Answer: 270
Step-by-step 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,
[tex]\frac{3}{20}=\frac{x}{1800}\\\Rightarrow\ x=\frac{1800\times3}{20}\\\Rightarrow\ x=270[/tex]
Hence, we need to send 270 texts to get the prize.
