Which of the following ordered pairs represents the solution to the system given below?
x − 3y = 12
2x + 6y = 60
(0,-4)
(12,0)
(3,21)
(21,3)

x − 3y = 12
2x + 6y = 60

x=12+3y

2(12+3y)+6y=60

24+6y+6y=60

24+12y=60

12y=60-24

12y=36

y=36/12

y=3

and since the only answer you have with y being 3 is 21,3 the answer is D.(21,3)

{ x - 3 y = 12  *  ( - 2)
  2 x + 6 y = 60 

- 2 x + 6 y = - 24
  2 x + 6 y = 60

          12 y =  36
                 
               y = 36 / 12

               y =  3

For x :

2 x + 6 y = 60

2 x + 6 * ( 3 ) = 60

2 x + 18 = 60

2 x = 60 - 18

2 x =  42

x = 42 / 2

x =  21

Answer D : ( 21,3)  

hope this helps!

3:40 p.m.

Step-by-step explanation:

Add 74 minutes to 1:25 p.m.; the improperly formed result witll be 1:99 p.m.; to express this properly, add 1 hour to this time and subtract 60 minutes from it:

2:39 p.m. (time at which Avery gets off the bus)

If Avery walked 61 minutes to get home and we want to know what time she arrived, we add 61 minutes to 2:39 p.m., obtaining 2:100 p.m., which must in turn be re-written as 3:40 p.m.

Avery arrived home at 3:40 p.m.

Note:  another way in which to do this problem is to add 74 minutes and 61 minutes, obtaining 135 minutes, and then adding 135 minutes to 1:25 p.m. and making the necessary adjustments to the result:

1:25 p.m. + 135 minutes = 1:160 p.m., or (recognizing that 120 min = 2 hours)

3:40 p.m.