x = 25% of 104 = 0.25(104) = 26
7 is 10% of y......7 = 0.10y......7/0.10 = y.....70 = y
n is 80% of y......n = 0.80y.....n = 0.80(70)......n = 56
y = a% of (n + y - x)
70 = a% (56 + 70 - 26)
70 = a%(100)
70 = 100a%
70/100 = a%
0.7 = a%
70 = a
so y is 70% of 100
