90-day forward1.8381 180-day forward1.8291 What opportunities are open to an investor in the following situations?

90-day forward          1.8381

180-day forward        1.8291

What opportunities are open to an investor in the following situations?

a.     A 90-day European put option to sell £1 for $1.86 costs $0.0200.

The answer, buy put and buy forward but I do not know why not sell put but buy put.

could you explain the detail please.