James bought 4 bottles of juice.
Solution:
Given that
Total Number of bottles bought by James = 15
There are two types of bottles that are bottle of juice and bottle of water.
Cost of one bottle of water =
Cost of one bottle of Juice =

Total amount spent on buying bottles =

Need to calculate number of bottles of juice bought by James.
Let’s assume number of bottles of juice bought by James be represented by variable x.
So Remaining bottles of out of 15 bottles will be bottle of water
So number of bottles of water =



Total amount spent on buying bottles = Price of x bottles of juice + Price of (15 – x) bottles of water
Solving above expression to get value of x.

As number of bottles of juice bought by James be represented by variable x, hence the number of bottles of juice bought by James is 4.