Note: Consider 84 instead of 83 because the value of x is a decimal value of 83 which is not possible.
Given:
Compound ratio of 7:5 and 8:x is 84:60.
To find:
The value of x.
Solution:
Compound ratio of 7:5 and 8:x is 84:60.



By cross multiplication, we get


Divide both sides by 1420.


Therefore, the value of x is 8.