Thursday, June 4, 2009

Two rich friends

One friend is saying to another: "If you give me $100, I will be twice richer than you." To this, second friend replied: "If you give me $10, I will be six times richer than you." How much each of the friends has? (from the old Russian puzzle book)


Alin Grin said...

The first friend has 40
The second friend has 170
If the first friend gives 100 to the second friend then:
140 and 70 first friend got twice as much.
if the second friend gives 10 to the first friend then:
30 and 180 the second friend got 6 times as much.

Marina Marshak said...

if x is a first person salary and y is the second
then x+100=(y-100)*2 => x=2y-300
(x-10)*6=y+10 => 6x=y+70 => 6(2y-300)=y+70

when you solve those 2 equesions you get that
x=40 and y is 170

Maria said...

Bravo, Alin and Marina - two alternative explanations and the same answer.

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