Answer:
10.31 pounds
Step-by-step explanation:
First, we multiply 1.3 x 2 because he is gaining 1.3 for the next TWO weeks.
1.3 x 2 = 2.6
Now, add 7.71 + 2.6 because that is the weight he started with.
7.71 + 2.6 = 10.31
Her brother will weight 10.31 pounds if he is 7.71 lbs and continues to gain 1.3 pounds each week for two weeks.
