Answer:
If Jenny gives her brother 28 marbles, they will have 59 marbles each.
Step-by-step explanation:
The key to finding this answer is a mean, or average. Find it for the number of marbles:
[tex]\text{Mean}=\frac{87+31}{2}= \frac{118}{2}=59 \text{ marbles}[/tex]
So, on average, each one should have 59 marbles.
Finally, to find out how many marbles Jenny should give to her brother, subtract the average (59 marbles) from her count:
[tex]87-59=28 \text{ marbles}[/tex]
This means Jenny would give up 28 of her marbles to her brother.
