Answer:
Luis has 30 cards
Step-by-step explanation:
To solve this problem, we need to setup a system of equations.
If we call the amount of cards Juan has "J", Pedro "P", Maria "M" and Luis "L", we have that:
J + P + M + L = 62
P = J/3
M = J - 3
L = 2J
Substituting P, M and L in the first equation, we have:
J + J/3 + J - 3 + 2J = 62
13J/3 = 62 + 3
13J = 65 * 3
J = 15 cards
The amount of cards Luis has is:
L = 2J = 2 * 15 = 30 cards