What does this mean? 20? is a three digit number which is divisible by the product of its first and third digits. what is the number?
2007-01-31 10:46:02 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
ok, so this means that you have a 3 digit number beginning with 20_
you need to find the 3rd digit
the condition is that the resulting 3 digit number has to be divisible (evenly, no remainder) by the 1st digit (2) times the 3rd digit (the one you choose)
your choices for digits are 0-9
0 : it can't be zero because 0*2 = 0 and you can't divide by 0
1: it can't be 1 because 2*1 = 2 and 201 is not divisible by 2
2: it can't be 2 because 202/(2*2) = 50.5 (not a whole number)
3: it can't be 3 because 203/(2*3) = 33.83333... (not a whole number)
4: it can't be 4 because 204/(2*4) = 25.5 (not a whole number)
5: it can't be 5 because 205/(2*5) = 20.5 (not a whole number)
6: it can't be 6 because 206/(2*6) = 17.166666... (not a whole number)
7: it can't be 7 because 207/(2*7) = 14.7857... (not a whole number)
9: it can't be 9 because 209/(2*9) = 11.61111... (not a whole number)
208/(2*8) = 13, which is a whole number so the answer is 8
Additionally, you could have eliminated all odd numbers to begin with, because you divide the odd number by 2 times the odd number, and odd numbers are not divisible by 2.
2007-01-31 11:00:38 · answer #1 · answered by branzillie 2 · 0⤊ 0⤋
if i were to put 3 in the last digit to get 203. then the product of the first and thrid digits is 2*3 = 6. is 203 divisible by 6? nope, so off to find another number.
there's only 10 numbers to go through, won't take u long
2007-01-31 18:52:47 · answer #2 · answered by wendywei85 3 · 0⤊ 0⤋
two hundred and "something" is a number that is divisible by 2 times "something". I suggest 204.
2007-01-31 18:54:55 · answer #3 · answered by trueblue88 5 · 1⤊ 0⤋
208
2007-01-31 18:53:37 · answer #4 · answered by lolypop 1 · 1⤊ 0⤋