Those familiar with Only Connect will know how this works. but a quick explanation will not go amiss.
You will see three phrases, one at a time. These are below, and now you have to work out the fourth phrase.
The three are:
(3 x 96 + 80) x 6
2 x 50 x 6
2 x 20 x 6
These are the standard number of balls that should be bowled in three of the four forms of professional cricket in England, from longest to shortest. These are the County Championship (96 overs on the first three days and 80 on the fourth day with six-ball overs), the Royal London One-Day Cup (a 50-over innings for both teams with six-ball overs) and the Vitality Blast (a 20-over innings for both teams with six-ball overs.
The fourth and shortest competition is The Hundred with a 100-ball innings for both teams, so the answer is
2 x 100