Set up two equations:

(1) 10x + 5y = 1225

(2) x + y = 170

Rearrange (2)

x = 170 - y

Substitute that into (1)

10(170 - y) + 5y = 1225

1700 - 10y + 5y = 1225

1700 - 5y = 1225

Move 5y to the other side

5y + 1225 = 1700

Subtract 1225 from each side

5y =475

Divide each side by 5

**y = 95**

Which means x = 170 - 95,

**x = 75**