2x + 3y = 45
x + y = 10......y = 10 - x
2x + 3(10 - x) = 45
2x + 30 - 3x = 45
-x + 30 = 45
-x = 45 - 30
-x = 15
x = -15 <====
and y = 25
Of 85% of cars sold where not black then 100-85% where black = 15%
let the number of cars sold be y
then 15%*y=300
y= 300 divided by 15%
= (300*100)/15
=2000
therefore 2000 cars were sold
たはたらさあらたはたはあらたさらやたはまさらたはまりあはらたはたさたはあらあらたはたひたはらたら、らま、らま、らまはたはたはさまらたらまはあはあらたはたひまひはたらたはまはたらまはた