Dependent Sample Help

#1
The question is asking the following:

The two data sets are dependent. Find to the nearest tenth (one decimal place).

A 64 53 57 63 51
B 29 30 27 25 22

This is what I did:

I added data set A = 288
I added data set B = 133
The differnce between the two data = 155
The mean (155/10) = 15.5
This answer isn't correct. What am I doing wrong? Please advise.

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