Question

Tina bought some nail polish and lip gloss at the store. The nail polish cost $4.50 per bottle and lip gloss cost $7 per tube. Tina bought 9 items and spent $50.50. How many of each item did she buy?

Answer 1

let Tina bought X number of nail polish any Y number of lip gloss.
then,      X+Y=9
           or,X=9-Y

Also,4.5 X+7 Y=50.5
  or,  4.5 (9-Y) +7 Y=50.5
  or,  Y =4.........................................(i)

so, X= 9-4
        = 5........................................(ii)
hence, she bought 5 nail polish and 4 lip gloss