I need help. I don't understand it. Still.

(b). Three guys Kojo, Mensah and Jack were required to fire and hit a target once as part of their Military training in order to join the forces in Iraq and Afghanistan. The probability that Kojo, Mensah and Jack hit the target are 1/2, 1/5 and 3/4 respectively. Find the following. (i) The probability that none of the three guys hit the target. (2.5 points) Soln