5 boys play both hockey and volleyball (30-20-15=5)
An explicit formula for a sequence allows you to find the value of any term in the sequence. A recursive formula for a sequence allows you to find the value of the nth term in the sequence if you know the value of the (n-1)th term in the sequence.
I think it would be around 7 lbs
(i could be wrong but i think this is about right)
