Answer:
Luke has 13 marbles
Step-by-step explanation:
t = number of marbles Tom has
l = number of marbles Luke has
t = 2l
t+l = 39
Substitute t = 2l into the second equation
2l + l = 39
Combine like terms
3l = 39
Divide by 3
3l /3 = 39/3
l = 13
Luke has 13 marbles
Tom has 2 * 13 = 26 marbles
