3rd grade question

[rcp1966]

Marco and his dad have an age difference of 25 years. the sum of their ages is 43. How old is Marco?

 

[cad]

marco is 9 years old

 

[Deleted member 4993]

Marco and his dad have an age difference of 25 years. the sum of their ages is 43. How old is Marco?

Since this is a 3rd grade problem - we should not use algebra. Then the best way to do this is educated guess as follows:

Lets look at middle of 43 - and say the dad's age is 22 and son is 21. But the difference is only 1 - we need 25

So let's add 10 years to Dad's age and subtract 10 from son's age - we get Dad = 32 and son = 11 → difference = 21

still not enough difference - so again subtract 5 from son's age and add 5 to Dad's age → we get Dad = 37 and son = 6 → difference = 31

oop's too much difference - let's add 2 to son's age and subtract 2 from Dad's age → we get Dad = 35 and son = 8 → difference = 27

oop's too much difference - let's add 1 to son's age and subtract 1 from Dad's age → we get Dad = 34 and son = 9 → difference = 25 ← we got it!!

So Dad's age is 34 yrs. and son's age is 9 yrs.

 

[stapel]

marco is 9 years old

Is there any particular reason you're resurrecting years-old threads? :shock:

 

[HallsofIvy]

And Marco isn't 9 years old any more!