The centroid is the point where the 3 medians meet. In the diagram, the centroid is M. A median is a line that joins the midpoint of the side opposite the angle opposite the midpoint. RC is the median of PQ. You might have to read this a couple of times to have it make sense.
To find RM, you have to realize that the centroid cuts the median line in a ratio of 1:2.
In this problem, you are given more information than you need. The median containing RM is RC. If CM is 7, RM will be twice as long which is 14.
Stack them on top of each other and find the common denominator then multiply to total the denominator. Ex. 1/4 denominator is 8. 4x2 is 8. So 1 times what equals 8. 1! Then you should a new fraction 8/8 which is equivalent to 1.
His brothers have 4 games He had 10 games So in total there are 14 games And if there are 2 cases and each one had the same amount, then in each one there would be 14÷2=7