math
posted by widyan .
Jimmy had a total of 163 apples and oranges. After selling 50% of all the apples and 20% of all the oranges, he had 110 fruits left. How many oranges did Jimmy have at first?

Let x = # of apples and y = # of oranges.
x + y = 163
x = 163  y
.5x + .8y = 110
Substitute 163y for x in last equation and solve for y. Insert that value into the first equation and solve for x. Check by inserting both values into the second equation. 
let the number of apples be x
let the number of oranges be y
x+y = 163 > y = 163x
.5x + .8y = 110
5x + 8y = 1100
use substitution
5x + 8(163x) = 1100
5x + 1304  8x = 1100
3x = 204
x = 68
he has 68 apples and 95 oranges at first