Xiao Qi ate two fifths, Xiao Jing ate seven twentieth, and finally there were 15 sweets left.

Two people ate * * *: 2/5+7/20 = 8/20+7/20 =15/20 = 3/4.

So: the remaining 1-3/4= 1/4 corresponds to 15 sugars.

The total number * * * is:15÷ (1/4) =15× 4 = 60.