We define that K@J is the product of j number from k in increasing order for positive integers K, J. For example, 6@4=6*7*8*9. If A=2020and B=2120, what is the value Q of the ratio A/B? Choose one:	A) 1/2	B) 1/3	C) 2/3	D) 1/4	E) 1/5
Q-&gt; A/B=20*21*……*39/21*22*….*39*40=20/40=1/2.   Therefore, the answer is 1/2.
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We define that K@J is the product of j number from k in increasing order for positive integers K, J. For example, 6@4=6*7*8*9. If A=2020and B=2120, what is the value Q of the ratio A/B?