Let's define first the variables.
let H be the number of bags of the type that cost 3.25 and P the number of bags of the type that cost 2.75.
since they sold a total of 156 bags we have that H+P=156
and from the other condition we obtain 3.25H+2.75P=455
now we can solve the system of equations.
from the first equation H=156-P
substituing the previous equality in the second one we obtain:
![3.25(156-P)+2.75P=455](https://img.qammunity.org/2023/formulas/mathematics/college/6imrlliekdw2yfoj9d8uljgzjkhrlc0x5e.png)
![507-3.25P+2.75P=455](https://img.qammunity.org/2023/formulas/mathematics/college/tj3ev9dheyeb318o4twilalkll2r2cf85z.png)
![(2.75-3.25)P=-53](https://img.qammunity.org/2023/formulas/mathematics/college/2rvqa2p6m5dfaixxblwi3ifqjmvtpgta8c.png)
![0.5P=53](https://img.qammunity.org/2023/formulas/mathematics/college/7bvo6bjrdeyu1p492r547yka8gp5tx1vyf.png)
![P=106](https://img.qammunity.org/2023/formulas/mathematics/college/fsawqoozv2c1l137qy6t8tesjeoi47mc2o.png)
now that we have P, we can replace it in the first equation obtaining that H=50
then the answer will be that they sold 50 bags of $3.25 and 106 bags of $2.75