Hello again >_<

The partially completed table gives the probability distribution for the number of breakdowns per week for a machine, based on historical data.

Breakdown per week 0_______1______2______3______4 or more

Probability_________X______ 0.4____ 0.22 ___0.12___0.06

Determine the probability that the number of breakdowns in a given week is at most one.

thank you very much for your help