1. You have that Karen made 40 cakes and she gives 1/5 to Andrew and 10% to Chris, then you have:
40 cakes=5/5=1
1/5 to Andrew⇒40x1/5=8
10% to Chris=40x0.10=4
1/5----8
x----4
x=4(1/5)/8
x=1/10
2. The fraction of the 40 cakes that she have left is:
1-1/5-1/10
Therefore, the answer is: 7/10
