Dexter plans to spend totally 8 hours on preparing
for his final. he will spend 3.5 hours on math. he needs
twice as much time on biology as on english. he plans to
take three 30-minute breaks in-between his study. how
long will dexter spend on studying biology?

2 hours

Step-by-step explanation:

Let the total time allotted for English be x

Hence the total time for Biology studies = 2x

Time allotted for Math = 3.5

Rest time = 30 min + 30 min +30 min = 90 min = 1.5 hrs

Total time for studies = x+2x+3.5+1.5 which is given as 8 hours

Thus

x+2x+3.5+1.5 =8

3x+5=8

3x=3

x=1

Hence time on English = 1 hours

Time for biology = 1 x 2 = 2 hours

step-by-step explanation:

the probability is 0