Answer:
5x + 15y =20 = - 3x +25y =75
= 8 minutes
Explanation:
5x + 15y =20 multiply all by 3 to get 15x
15x +45y=60
- 3x +25y =75 multiply all by -5 to get 15x
15x -125y = -375
rewrite ans together
15x +45y=60
15x -125y = -375
-80y = -315
y = -315/ - 80
y = 3.9375 = y= 4 substitute to find x
5x + 15(4 )=20
5x +60 = 20
5x=-40
x= -40/5
x=-8
15x +45(4)=60
15x +180 =60
15x =-120
x=-8