First you can find \(\frac{31}{45}\) of 90.
90 x \(\frac{31}{45}\) = 62
Next, you have $62 left and spent @@MATH_TOKEN_2@@ of it. Meaning you have @@MATH_TOKEN_3@@ of 62 left.
62 x @@MATH_TOKEN_4@@ = about 53.14285
As your answer is not a whole number, you could round according to whatever guidelines your homework has given you (for example - rounding to the 2nd decimal place $53.14)