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**Question**

7) The probability that any postcard posted in Portugal on Monday is delivered to the UK within a week is 0.62.

The probability that any postcard posted in Portugal on Friday is delivered to the UK within a week is 0.41.

a) Anna is on holiday in Portugal.

She posts 15 postcards to the UK on Monday.

How many of her postcards can she expect to be delivered within a week?

The probability that any postcard posted in Portugal on Friday is delivered to the UK within a week is 0.41.

a) Anna is on holiday in Portugal.

She posts 15 postcards to the UK on Monday.

How many of her postcards can she expect to be delivered within a week?

**[2 marks]**

b) Sergio is in Portugal.

He posts one postcard to the UK on Monday.

He posts another postcard to the UK on Friday.

i) Complete the probability tree to show the possible outcomes for the postcards.

**[2 marks]**

ii) Calculate the probability that only one of Sergio’s postcards is delivered within a week.

**[3 marks]**