Answer
Find out the what fraction of the sandcastle did they build together .
To prove
Let us assume that the fraction of the sandcastle they build together be x .
As given


Than the equation becomes

L.C .M of (3,7) = 21
solving


Therefore the fraction of the sandcastle did they build together be

Hence proved
Answer: If you have solved to get x=6 just plug that back into the problem. You get 50
Step-by-step explanation:
Answer:
7/80
Step-by-step explanation:
Given that: P(B) = 7 / 20, P(A|B)= 1 / 4
Bayes theorem is used to mathematically represent the conditional probability of an event A given B. According to Bayes theorem:

Where P(B) is the probability of event B occurring, P(A ∩ B) is the probability of event A and event B occurring and P(A|B) is the probability of event A occurring given event B.
