Answer:
1/180
Step-by-step explanation:
1/3 + 1/6 + 1/9 + 1/12 + 1/15 + 1/18 =
= 60/180 + 30/180 + 20/180 + 15/180 + 12/180 + 10/180
= 49/60
The sum of the six fractions is 49/60.
We want the sum of 4 fractions to be 2/3 = 40/60
49/60 - 40/60 = 9/60
We need to remove 2 fractions whose sum is 9/60.
1/12 + 1/15 = 5/60 + 4/60 = 9/60
Remove 1/12 and 1/15.
1/3 + 1/6 + 1/9 + 1/18 =
= 60/180 + 30/180 + 20/180 + 10/180
= 120/180 = 2/3
The product of 1/12 and 1/15 = 1/180.
