two digit number

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rajendrarama
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two digit number

Postby rajendrarama » Fri Oct 21, 2011 9:07 pm

which number is described by the following clues? it is a multiple of three, multiple of five, the sum of digits is even and the numbe is between 1 and 100?

I thought of 15, 60 and 75. But is there any equation kind of format to find the exact answer.
Can anyone help in writing equations to find the exact answer.

Thanks in advance

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maggiemagnet
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Re: two digit number

Postby maggiemagnet » Tue Nov 01, 2011 3:05 pm

rajendrarama wrote:which number is described by the following clues? it is a multiple of three, multiple of five, the sum of digits is even and the numbe is between 1 and 100?

I thought of 15, 60 and 75. But is there any equation kind of format to find the exact answer.
Can anyone help in writing equations to find the exact answer.

I don't think equations would help much. If the number is "x", then you get x = 3a, x = 5b; x = 10m + n, m + n = 2c; and 1 < x < 100. That's four equations in six variables. You can't solve that with algebra. So guess-n-check is probably the way to go here.
:clap:


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