Problema Solution
Lady sells Kids hats for $4 adult hats for $7. She sold 120 hats, and collected $720. How many adult hats did she sell?
Answer provided by our tutors
let kids = x, hats = y
then,
x+y = 120 x7
4x+7y = 720
==> 7x+7y = 840
4x+7y = 720
subtract these two, then 3x = 120 ==> x = 40
y = 80
(40 for kids, 80 for adults)