There's 9 choices for the first digit and 4 choices for the last digit. The number of choices for the 2nd and 3rd digits is 90 if 2 numbers are different. or 100 if duplicates are allowed.
If duplicates are allowed the answer is 9 * 100 * 4 = 3600 possible numbers.
850. If there is 17 red beads for every 150 beads Then you would divide 7500 by 150 and you get 50. Then multiply 50 with 17 and your answer is 850 red beads. 7500/150=50. 50 x 17= 850.
Is %
=
of 100
x 6
=
550 100
cross multiply and divide
100x=3300
divide both sides by 100
x=33