问一题机井

evildoll

4. k is a 2-digit positive integer, the value of k is 6 times of the unit digit, what is the value of k? D
(1). the ten digit is 4 greater than unit digit.
(2). the sum of the two digits is a two-digit integer.

evildoll

en,i think it questionable
when suppose unit digit=b,ten digit=a
so 10a+b=6b
   a=b+4
then a=-4
faint

isenetlab12

the problem discription must be wrong since "the value of k is 6 times of the unit digit" means k<=54 then only 51 and 40 can meet the condition (1), but violate the "the value of k is 6 times of the unit digit" so the condition (1) may be the incorrect record; from condition (2), we can find 48 is the only value can meet the question. we can list all the numbers 19, 29,28,39,38,37,49,48,47,46 agree?

猫猫头

K=a+10b=6b==>a+4b=0