Jingjing finished alone, moved x times and had y books.

Then:

Doudou alone: x-5

Speed of jingjing: y/x

Speed of pea: y/(x-5)

Partnership processing is:

6 × (y / x)+ 6 ×(y / x-5) = y

Divide both sides by y at the same time, which is:

6/x + 6/(x-5) = 1

6(x-5) +6x = x？ -5 times

6x -30 +6x - x？ +5x =0

x？ - 17x +30 = 0

(x- 15)(x-2)=0

Solution:

x 1 = 15

X2 = 2 (truncated)

Jingjing moved alone 15 times, and Doudou moved alone 10 times.