Poll of the Day > MIT Applicants were asked to solve this VERY DIFFICULT MATH QUESTION..Can you???

(+) Yeah! (+)

All students who were trying to attend the prestigious Massachusetts Institute of Technology Entrance exam were asked this over 100 year old Math question that stumped a lot of students.and it sounds relatively easy but the question isn't as simple as it sounds as only the brightest math wizzes know the equations to do it....can you solve it?.

https://i.imgur.com/cEaeRoM.jpg
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I misread the question and voted wrong. I think it oughta be 48 and 16 if the question is what were the age and not what is their current age.

I used these equations where x is the dad's current age and y is the son's current age. I think I did it correctly.

x - 2 = 3(y - 2)

x + 14 = 2(y + 14)


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x = older person's current age
y = younger person's current age

x-2 = 3(y-2) ==> y = x/3 -2/3 +2 ==> y = x/3 +4/3
x+14 = 2(y+14)

Subbing in the y= to the 2nd equation...
x+14 = 2(x/3 +4/3 +14)
x/2 +7 = x/3 +46/3
x/2 - x/3 = 46/3 - 7
x/6 = 25/3
x = 50

y = 50/3 + 4/3 = 18

Check: 2 years ago, x -2 = 48; y - 2 = 16 (3x the age)
Check: 14 years forward, x+14 = 64; y+14 = 32 (2x the age)

I kept messing up b/c I forgot to account for the -2 and +14 on the "y side", lol
That's why you sanity check the results, to see something's clearly wrong.

No one has voted for 48 and 16? I voted for 50 and 18 but since the question ask what were their ages, would 48 and 16 be the correct response?

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InfestedAdam posted...

No one has voted for 48 and 16? I voted for 50 and 18 but since the question ask what were their ages, would 48 and 16 be the correct response?

The whole word problem is written poorly. It switches from "I" talking to "you" abruptly to 3rd person (their), and in doing so makes it linguistically unclear if the use of "were" (also a poor choice for clarity) is inferring the past state of 2 years ago or...since it's now a purely a clinical 3rd person narrative, is simply asking in the sense of "what were the ages (now) to make both the past and future conditions possible?"

I could see it going either way but logically makes the most sense to be asking what age they are in the present. If you showed all your work and the teacher tried to not give you credit b/c you didn't understand his failed attempt at English, he's a dick.
*shrug*

streamofthesky posted...

The whole word problem is written poorly. It switches from "I" talking to "you" abruptly to 3rd person (their), and in doing so makes it linguistically unclear if the use of "were" (also a poor choice for clarity) is inferring the past state of 2 years ago or...since it's now a purely a clinical 3rd person narrative, is simply asking in the sense of "what were the ages (now) to make both the past and future conditions possible?"

I could see it going either way but logically makes the most sense to be asking what age they are in the present. If you showed all your work and the teacher tried to not give you credit b/c you didn't understand his failed attempt at English, he's a dick.
*shrug*

that's because this is not an MIT question, it's a 6th grade math problem that someone just didn't translate properly. Meaning, whoever can't solve this, never passed 6th grade

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46 and 2 is the right answer

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3(x - 2) = (y - 2)
3x - 6 = y - 2
3x - y - 4 = 0

2(x + 14) = (y + 14)
2x + 28 = y + 14
2x - y + 14 = 0

3x - y - 4 = 0
2x - y + 14 = 0
===================
x - 18 = 0
x = 18

2(18) - y + 14 = 0
36 + 14 = y
y = 50


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the thing is, if it's a multiple choice question, it's far quicker to trial and error until one or neither fits, solving for x is a waste of time

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What_The_Chris posted...

solving for x is a lot funner though

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If the question was multiple choice, then you only had to take each answer given, subtract 2 years from each age, divide the older age by the younger age, and find which gives the answer of three. Since only one of those answers was correct to get 3 you then had to test that answer to make sure that adding 14 years to each age would make the older age twice the younger age. I'll admit that way is a sort of cheat, but you don't need a complex set of formulas to solve it if the question was multiple choice.

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