Tolc med 2015 probability question

[nihantokar]

can someone explain briefly how to approach this question? the answer is E 0.96

[Juliette]

hi

there are 3 possible scenarios
wait less than 10 both times = 0,8 * 0,8
only wait less than 10 the first time = 0,8 * 0,2
or only wait less than 10 the second time = 0,2 * 0,8

total probability = 0,8 * 0,8 + 0,8 * 0,2 + 0,8 * 0,2 = 0,96