a₁*b₁ = 0,68*a*b,
a₁ = a*(100 - x)/100,
b₁ = b*0,85,
a*b*(100-x)*0,85/100 = 0,68*a*b,
(100-x)*0,85/100 = 0,68,
(100 - x)*0,85 = 68,
85 - 0,85*x = 68,
0,85x = 85 - 68 = 17,
x = 17/0,85 = 17*100/85 = 17*100/(5*17) = 100/5 = 20.
ответ. 20.
a₁*b₁ = 0,68*a*b,
a₁ = a*(100 - x)/100,
b₁ = b*0,85,
a*b*(100-x)*0,85/100 = 0,68*a*b,
(100-x)*0,85/100 = 0,68,
(100 - x)*0,85 = 68,
85 - 0,85*x = 68,
0,85x = 85 - 68 = 17,
x = 17/0,85 = 17*100/85 = 17*100/(5*17) = 100/5 = 20.
ответ. 20.