Question

The ratio of Stanley's colored markers to Jiayi's markers was 4:1. Jiayi had a big art project to work on, so Stanley let her borrow 50 markers. As a result, the ratio of Stanley's markers to Jiayi's changed to 2:3. If Jiayi ended up with 75 markers, how many markers did Stanley start with?

Answer 1

Let
x= Stanley's colored markers
y=Jiayi's markers
We have the following system:
Initial relationship:
4/1=x/y
Stanley let her borrow 50 markers:
2/3=(x-50)/(75)
x-50=(2/3)*75
x=(2/3)*75 + 50 =100
Answer:
Stanley start with 100 markers