Answer:
23 years old and 8 years old.
Step-by-step explanation:
Let's denote Xiao Kun's current age as K and Xiao Cheng's current age as C.
Three years ago, Xiao Kun's age was K - 3 and Xiao Cheng's age was C - 3.
According to the given information:
Three years ago, Xiao Kun's age was four times that of Xiao Cheng:
K - 3 = 4 (C - 3)
Two years later, Xiao Kun's age was 15 years older than Xiao Cheng's:
K + 2 = C + 2 + 15
Now, we can set up a system of equations to solve for
Equation 1: K - 3 = 4 (C - 3)
Equation 2: K + 2 = C + 17
Let's solve this system:
From Equation 1:
K - 3 = 4C - 12
K = 4C - 9
Substitute this expression for K into Equation 2:
4C - 9 + 2 = C + 17
Combine like terms:
4C - 7 = C + 17
Subtract C from both sides:
3C - 7 = 17
Add 7 to both sides:
3C = 24
Divide by 3:
C = 8
Now that we know Xiao Cheng's current age (C = 8), substitute this back into the expression for K:
K = 4(8) - 9
K = 23
So, Xiao Kun is 23 years old, and Xiao Cheng is 8 years old this year.
I hope this helps :)
