Answer:
Jeremy is 12 years old
Explanation:
Jeremy age=X
Sister age=Y
1. X+Y=29 (sum of their ages)
2. X=Y-5 (he is 5 years younger than his sister)
*Substitute eq 2 into eq 1
Y-5+Y=29
2Y=29+5
2Y=36 (divide both sides by 2)
Y =17
Substitute value of Y into eq 1 to find X
X+17=29
X=29-17
X= 12
Checking answer:
12+17=29
17-5=12
Hence why Jeremy is 12