Answer:
40 tarts
Explanation:
Lindsey had 400 tarts to start with, then she sold off 3/5 of them. Hence find the number of tarts left (2/5 of the original amount). Then she sold 1/4 of the remaining tarts. Therefore, find 1/4 or 2/5 of 400. The equation would be;
![((1)/(4))((2)/(5))(400)](https://img.qammunity.org/2022/formulas/mathematics/college/ms1wguut7pqby17ktllda77yf8p16duvjb.png)
Now one just has to solve the equation;
![(1)/(10)(400)](https://img.qammunity.org/2022/formulas/mathematics/college/rg5djx0s5m5mzj844g25acmsgx1286dus0.png)
40