Question

Bob sells hats and scarves.

At the start of the day, he has : hats : scarves = 4 : 3
During the day he sells 25 hats.
At the end of the day, he has: hats : scarves = 7 : 9

How many scarves does Bob have in his store

Answer 1

We define variables:
x: number of hats
y: number of scarves
We have the following equations:
x / y = 4/3
x-25 / y = 7/9
Solving the system of equations we have
x = 60
y = 45
Answer:
Bob has 45 scarves in his store