Let
x--------------> a number
we know that
three sets of a sum of a number and four----------> 3(x+4)
the sum of 7 times the same number and 13--------> 7x+13
therefore
(Three sets of a sum of a number and four) are added (to the sum of 7 times the same number and 13) ----------> [3(x+4)] + [7x+3]
[3(x+4)] + [7x+3]------> [3x+12] + [7x+3]=10x+15
the answer is 10x+15
