Answer:
Andrew has 30 goldfish and Todd has 10 goldfish
Step-by-step explanation:
Lets call A the number of goldfish Andrew has and T the number of goldfish Todd has.
Andrew has 10 more goldfish than Todd:
A = T + 10
Together they have 50 goldfish:
A + T = 50
Lets replace A = (T + 10) in the las equation:
T + 10 + T = 50
Lets solve T in this equation:
2T + 10 -10 = 50 -10
2T /2 = 40 /2
T = 20
Todd has 20 goldfish
Now lets calculate A = T + 10 = 20 + 10 = 30
Andrew has 30 goldfish
