Maggie spent $2.75 on cheese.
As the fruit are weighed in fractions of pounds that are not similar, you need to convert them to a similar form that will allow them to be added.
Convert them to decimals:
1/8 = 0.125
1/4 = 0.25
1.25 = 1.25
The cost of the fruit is therefore:
= (Total pounds of fruit bought) x Cost per pound
= (0.125 + 0.25 + 1.25) x 0.8
= 1.625 x 0.8
= $1.30
The amount spent on cheese is:
= Total amount spent - Amount spent on fruit
= 4.05 - 1.30
= $2.75
Maggie, therefore, spent $2.75 on cheese.