Answer:
8 cookies left to be baked
Explanation:
Len
Len bakes 1/3 of 30 cookies
To find 1/3 of 30, divide 30 by 3 then multiply by 1:
Therefore, Len bakes 10 cookies
Sallesh
Sallesh bakes 2/5 of 30 cookies
To find 2/5 of 30, divide 30 by 5 then multiply by 2:
Therefore, Sallesh bakes 12 cookies
Cookies left to bake
To calculate how many cookies are left to bake, subtract the found number of cookies Len and Sallesh have baked from 30:
30 - 10 - 12 = 8
So there are 8 cookies left to be baked.