I dont understand this please dont leave a link

Answer:
185...not 100% sure my equation is actually correct though.
Step-by-step explanation:
15x + 20
15(11) + 20
165 + 20
185
In case you're wondering...15 represents the amount it increases by (45 - 30) and 20 is there because when "At the end of the week" is 0, "Insect population" is 20.