**Answer:**

t+f>420

**Step-by-step explanation:**

It only said variable so i only use the t and f but if it doesnt said IN TWO VARIABLES the answer would be 20t+50f>420.

**Answer:**

t+f>420

**Step-by-step explanation:**

It only said variable so i only use the t and f but if it doesnt said IN TWO VARIABLES the answer would be 20t+50f>420.