Answer:
x + y = 84
Step-by-step explanation:
Given
x : y : z = 5 : 1 : 3, then
[tex]\frac{x}{y}[/tex] = 5 ( multiply both sides by y )
x = 5y ←
and [tex]\frac{y}{z}[/tex] = [tex]\frac{1}{3}[/tex] ( cross- multiply )
3y = z
Substitute z = 3y into z - y = 28
3y - y = 28
2y = 28 ( divide both sides by 2 )
y = 14 ← ←
Substitute y = 14 into x = 5y
x = 5 × 14 = 70 ← ←
Substitute y = 14 into z - y = 28
z - 14 = 28 ( add 14 to both sides )
z = 42 ← ←
Thus x = 70, y = 14 and z = 42
Hence x + y = 70 + 14 = 84
