Randy had a lot of homework tonight. he needs to work for 45 minutes on social studies 40 minutes on science and 1 hour and 15 minutes on math. it will also take him 10 minutes to get ready for bed. if he wants to be in bed at 10: 00on what time does he need to start his homework?

He needs to start his homework at 7:10.

Step-by-step explanation:

Hi, to answer this question we have to add all the times:

45 min (social studies)

40 minutes (science)  

75 minutes (math) (1 hour and 15 minutes = 75 minutes)

10 minutes (to get ready)

Mathematically speaking:

45+40+75+10 = 170 minutes

If 60 minutes equals to 1 hour:

170/60 = 2.83 =  

The hour is the integer part (2 hours)

The minutes is the decimal part multiplied by 60

0.83 x 60 = 50 minutes

So, 2 hours and 50 minutes, before 10:00.

10:00 -2:50 = 7:10

x=half

step-by-step explanation:

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18