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Problem 18


The number of solutions in positive integers of 2x + 3y = 763 is:

Solution

Solving 2x + 3y = 763 for x, we have x =. Since x is a positive integer, 763 - 3y must be a positive even number, so that y must be a positive odd integer, such that . There are 254 multiples of 3 less than 763, half of which are even multiples and half, odd multiples. Therefore, there are 127 possible solutions to the given equation under the stated conditions.