Answer:
[tex]\frac{B}{5} + 3[/tex]
Step-by-step explanation:
B: number of marbles
Bob got 15 marbles: [tex]B+15[/tex]
Bob gives away 1/5 of his marbles. So, let's multiply our first expression by 1/5
[tex](B+15) X\frac{1}{5}[/tex]
Next, apply the distributive property of multiplication
[tex]\frac{B}{5} + \frac{15}{5} = \frac{B}{5} + 3[/tex]
To the initial B marbles that Bob has, plus 15 aditional marbles he got later, we multiply it by 1/5 applying its distributive porperty to obtain the number of marbles that Bob now has