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This problem trains for: SAT-I, AMC-8, GMAT.

The average of three integer numbers is divisible by 5. Which of the following values cannot be the sum of the numbers?

The average a of three integers x, y, z is given by:

equation

If the average is divisible by 5 then it must be integer and be a multiple of 5:

equation

where k is an integer.Therefore,

equation

the sum of the numbers must be a multiple of 15. The only choice that is not divisible by 15 is 145.