Well it have to be D because 32 and 20 can not go into 64 to 40 because 32 times 64 is 2048 and 64 times 20 is 1280 and if it was 40 times 32 and 20 it will still be higher. I HAVE FAITH IN YOU.
X can equal 10,000 because 10,00 divided by 2 is 5000, which is 4 digits
8.4/10
Every time you are dividing by 10 the decimal moves 1 time to the left so
8.4/10 is..
.84
you have it right 5 is 1 you just divide it by 10 again but for #7 and 10 its 8 over 10 and 6 over 10 cause its not in the 10s yet hope i helped