A father is now three times as old as his son. In five years the sum of their age will be 58 years. Find their present ages
2 answers
Arswer
f = father's present ages
s = son's present ages
A father is now three times as old as his son means:
f = 3 s
In five years father will be f + 5 yrs old, son will be s + 5 yrs old.
The sum of their age will be 58 years means:
f + 5 + s + 5 = 58
f + 10 + s = 58
Subtract 10 to both sides
f + s = 48
Replace f by 3 s in this equation
3 s + s = 48
4 s = 48
s = 48 / 4 = 12
f = 3 s = 3 ∙ 12 = 36
Father is now 36 yrs old.
Son is now 12 yrs old.
Check result.
A father is now three times as old as his son:
f / s = 36 / 12 = 3
In five years the sum of their age will be 58 years:
36 + 5 + 12 + 5 = 41 + 17 = 58
s = son's present ages
A father is now three times as old as his son means:
f = 3 s
In five years father will be f + 5 yrs old, son will be s + 5 yrs old.
The sum of their age will be 58 years means:
f + 5 + s + 5 = 58
f + 10 + s = 58
Subtract 10 to both sides
f + s = 48
Replace f by 3 s in this equation
3 s + s = 48
4 s = 48
s = 48 / 4 = 12
f = 3 s = 3 ∙ 12 = 36
Father is now 36 yrs old.
Son is now 12 yrs old.
Check result.
A father is now three times as old as his son:
f / s = 36 / 12 = 3
In five years the sum of their age will be 58 years:
36 + 5 + 12 + 5 = 41 + 17 = 58
2 answers