The numerator of a fraction is 4 less than the denominator. If 1 is added to the numerator, the simplified fraction is (4/5). What is the fraction?
一个分数的分子比分母少4，如果分子加上1，化成最简分数是(4/5)，这个分数是多少
<gadget id="calculator">11 / 15</gadget>
<output>11/15 = around 0.733333</output>

<result>11/15 = around 0.733333</result>