The positive integers a and b leave remainders of 4 and 7, respectively, when divided by 9. What is the remainder when a − 2b is divided by 9? Select.
A) 5	B) 6	C) 7	D) 8	E) 9
a=9x+4   so a could be 4, 13,22, 31,40,49,58,67,76,85   b=9y + 7   so b could be 7,16,25,34,43   Selecting any random number for a and b such that a-2b is positive number,   say a=22, b=7 =&gt; 2b=14   Hence a-2b = 8 Hence remainder when divided by 9 =8   say a=67, b=25 =&gt; 2b=50   Hence a-2b = 17 Hence remainder when divided by 9 is again 8   say a=49, b=7 =&gt; 2b=14   Hence a-2b = 35 Hence remainder when divided by 9 is again 8   Answer is 8.   ANSWER:8
<result>D</result>
The positive integers a and b leave remainders of 4 and 7, respectively, when divided by 9. What is the remainder when a − 2b is divided by 9?