Hello posters, i am just wondering if you could help me out here; I have my GCSE exam in two days and having left school without a mark scheme - please could you just tell me the answer to question below so I can see whether i got it right. Thanks in advance.

The probability that a bag of rice weighs less than 260g is 0.3.

Four Bags are chosen at random

What is the probability that exactly one bad weighs less than 260g?

You may use p⁴ + 4pq³ + 6p²q² + 4pq³ + q⁴