(1) Suppose that the first infected person infected X people on the first day.

So on the first day * * * caught a cold X+ 1 person.

The next day * * * caught a cold (X+ 1)X people.

Two days * * * cold X+ 1+(X+ 1)X=36.

X=5

(2) On the third day, 36+36×3= 144 people caught a cold.

The fourth day144+144×1= 288 people.

No, you can ask.