1:4
The pattern in the number sequence is that every number is 4 times larger than the one before it. In ratio form, 1:4 would be the representation of the pattern.
We will use B for the number of baseball cards and H for the number of hockey cards.
B = 5H
B + H = 840
Use substitution by plugging 5H in for B in the second equation.
5H + H = 840
6H = 840
H = 140
If there are 140 hockey cards, then there are 5*140 = 700 baseball cards.
So the answer is 700.
Using formula a^2- b^2 = (a-b)(a+b)
Answer:
It is not a valid sample because it is not a random sample of the population.
