{7x of 5 + 7Y of 5 = 210 {7x of 5 × 0.8 + 7Y of 5 × 0.8}

{7x of 5 + 7Y of 5 = 210 {7x of 5 × 0.8 + 7Y of 5 × 0.8}

7x / 5 + 7Y / 5 = 210
7(x+y)=5*210
x+y=150
5 / 7X × 0.8 + 5 / 7Y × 0.9 =?
0.56x+0.63y=5?
0.56(x+y)+0.7y=5?
0.56*150+0.7y=5?
0.7y=5?-84