Answer:
Daniel is 8 years old now
Explanation:
Let Kevin's age now be K and let Daniel's age now be D
"Kevin is 3 times as old as Daniel"
Translation: K = 3D
"4 years ago, Kevin was 5 times as old as Daniel"
4 years ago Kevin's age = K - 4
4 years ago Daniel's age = D - 4
4 years ago, Kevin was 5 times as old as Daniel.
Translation: K - 4 = 5(D - 4)
K - 4 = 5D - 20
Simplify this equation:
Add 4 to both sides:
K - 4 + 4 = 5D - 20 + 4
K = 5D - 16
Substitute K = #D:
3D = 5D - 16
Subtract 5D from both sides:
3D - 5D = - 16
-2D = -16
or
2D = 16 (multiply by - 1)
D = 16/2 = 8
and
K = 3D = 3 x 8 = 24
Now, Kevin is 24 years old and Daniel is 8 years old
Verify
If Kevin is 3x older than Daniel who is 8 now,
Kevin's age now = 3 x 8 = 24 Check
4 years ago, Daniel was 8 - 4 = 4 years
4 years ago, Kevin was 24 - 4 = 20
Kevin's age 4 years ago = 5 x 4 = 20 Check