Paper 2 · Statistics, probability

Of the pupils who went on a school trip, 16 were from Form 2 and 64 from Form 4, out of 1080 pupils at the whole school. Find, as a single fraction in its lowest terms, the probability that a pupil chosen at random from the whole school went on the trip and was in either Form 2 or Form 4.

Derived from ZIMSEC Mathematics Paper 2, June 1999, Q3