Answer:
5
Step-by-step explanation:
b(2)=b(2-1)+12
b(2)=b(1)+12
b(2)=-7+12
b(2)=5
Let x = the number of marbles Tim has
Let 2x = the number of marbles Sue has
x + 2x + 15 = 63
3x = 48
x = 16 marbles
Tom and Sara are 12, and Andrew is 4
