Answer:
Daniel is 8years old
Step-by-step explanation:
Let the age of Kelvin be K
Let the age of Daniel be d
Kelvin is 3 times as old as Daniel. This is written as:
K = 3d (1)
Four years ago:
Kevin's age is: K — 4
Daniel's age is: d — 4
But 4 years ago, we were told that Kevin was 5 times as old as Daniel. This is illustrated below as:
K — 4 = 5 (d — 4)
Clearing the bracket, we have:
K — 4 = 5d — 20
K = 5d — 20 + 4
K = 5d — 16 (2)
Substituting the value of K from equation 2 into equation 1:
K = 3d
5d — 16 = 3d
Collect like terms
5d — 3d = 16
2d = 16
Divide both side by 2
d = 16/2
d = 8years
Therefore, Daniel is 8years old.
