Answer:
Step-by-step explanation:
If "a" represents the number of adult smoothies sold, then 260-a is the number of smoothies sold to children. The total revenue is ...
3a +1(260-a) = 675
2a +260 = 675 . . . . . . eliminate parentheses
a + 130 = 337.5 . . . . . . divide by 2
a = 207.5 . . . . . . . . smoothies sold to adults
260-a = 52.5 . . . . . smoothies sold to children
_____
For the given numbers, this is the way it works out. The "half" values suggest there is a typo somewhere, possibly in the curriculum material. Talk to your teacher about this one.