{a, d, e, m, r, s, t}. How many different passwords are possible if the second and fourth letters will be vowels and the other two letters wonât be vowels (repeated letters are possible)?.

White shapes and black shapes are used in a game. some of the shapes are circles. while the rest are squares. the ratio of the number of white shapes to the number of black shapes is 5: 11. the ratio of the number of white cicrles to the number of white squares is 3: 7. the ratio of the number of black circles to the number of black squres is 3: 8. work out what fraction of all the shapes are circles.