Amount financed
137,900−137,900×0.20
=110,320
number of thousands
110,320÷1,000
=110.32
Multiply it by the monthly payment per thousands
110.32×7.34
=809.7488
Now multiply it by the number of months in a year
809.7488×12 months
=9,716.9856
Multiply it by the number of years
9,716.9856×30
=291,509.568
Now the total amount of interest charged
291,509.568−110,320
=181,189.568 round your answer
=181190...answer
Hope it helps