Calculating the Weight of Apples in Fruit Salad

Maria is making fruit salad using apples and bananas. She uses a total of 2.5 pounds of fruit, where the weight of the apples is represented by the variable $$a$$ and the weight of the bananas is represented by the variable $$b$$. Maria knows that she used 1.75 pounds of bananas. How many pounds of apples did she use? You need to set up the equation and solve for $$a$$.