Answer:
Yvonne is 22
Samuel is 18
Step-by-step explanation:
y is age of yvone, s is age of samuel
Write 2 equations:
y + s = 40
y = s + 4
Substitute (s + 4) into y in the first equation:
s + 4 + s = 40
Solve:
2s + 4 = 40
2s = 36
s = 18
Substitute 18 for s in either equation:
y + 18 = 40
Solve:
y = 22
