Explanation:
1) You have to find the total he spent on Sunday
108+54=162 dollars he spent on Sunday
2) Now to have to find the total amount he spent on both days.
162+108=270 dollars he spent both days
3) Now you put the radio together
Saturday:total
108:total
108:270
4)Last you have simply unless said other wise.
108:270
Divide each side by 54
2:5
5)Final answer
2:5