littlesharaih
The sum of the digits of a two-digit number is 12. If the units digit is 3 times the tens digit, find the number.
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hoblos
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let a be the units digit and b be the tens digit
the number = 10b +a
to find a and b we must solve the system
a+b =12
a= 3b
can you solve it ??
littlesharaih
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I'm not understanding
hoblos
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you dont understand the part that the two digit number = 10b + a ??
littlesharaih
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I don't understand how we start at 10b+a and then we go to a+b=12
hoblos
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no! these two parts are not related directly..
10a+b is the general form of any two digits number
but a+b =12 is concluded from the given ( The sum of the digits of a two-digit number is 12)
littlesharaih
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|dw:1344293939890:dw|
littlesharaih
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is this correct?
hoblos
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b=3 is correct
but then you must replace (b=3) in the equation a+b=12 to get a
and then add 10b +a
littlesharaih
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therefore my answer is 39
hoblos
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yes it is.. good job :)
littlesharaih
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thank you!!!
hoblos
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glad to help :)