how many cheez coockies did she bake

Question

mrs lim backed 480 cheez cookies and chocolate cookies, she gave 75% of her cheez cookies * 50% of her choc cookies to her mother, she was left with 160.

Answer 1

x = # of cheez

y = # of chocolate

x+y = 480

0.25x + 0.5y = 160 <-- gave away 75%, so 25% remain; kept half of the chocolate

y = 480-x

25x+50y = 16000

25x + 50(480-x) = 16000

25x + 24000 - 50x = 16000

-25x = -8000

x=320

started with 320 cheez and 160 chocolate

gave away 240 cheez and 80 chocolate

80 cheez and 80 chocolate remain, which is 160