SOLUTION: Seven times a two digit no. equals four times the number with digit reversed find the number if the sum of its digits is 3

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Question 761968: Seven times a two digit no. equals four times the number with digit reversed find the number if the sum of its digits is 3
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +u+ = the units digit
Let +t+ = the tens digit
-----------------------
The value of the number is +10t+%2B+u+
given:
(1) +7%2A%28+10t+%2B+u+%29+=+4%2A%28+10u+%2B+t+%29+
(2) +t+%2B+u+=+3+
---------------
(1) +70t+%2B+7u+=+40u+%2B+4t+
(1) +66t+=+33u+
(1) +2t+=+u+
by substitution:
(2) +t+%2B+2t+=+3+
(2) +3t+=+3+
(2) +t+=+1+
and
(2) +t+%2B+u+=+3+
(2) +1+%2B+u+=+3+
(2) +u+=+2+
The number is 12
check:
(1) +7%2A%28+10t+%2B+u+%29+=+4%2A%28+10u+%2B+t+%29+
(1) +7%2A%28+10%2A1+%2B+2+%29+=+4%2A%28+10%2A2+%2B+1+%29+
(1) +7%2A12+=+4%2A21+
(1) +84+=+84+
OK