Question

I’m very tired and Can anyone can help me? Here’s the question: Samantha has a riddle for her sister. Find a pair of integers x and y that satisfy 7x+3y=64 and one of the integers is 3 times the other. Please explain.

Answer 1

I: 7x+3y=64
II: assume y=3x (one of the integers is 3 times the other)
substitute y=3x from II into I:
7x+3y=64
7x+9x=64
16x=64
x=4

insert x=4 into II:
y=3x
y=3*4
y=12

so the valid pair is x=4, y=12