The digits 1, 2, 3, 4, 5, 6, and 7 are written on separate cards. Three are drawn and placed in order of drawing. In how many ways can numbers greater than 500 be formed?
The numbers 1,2,3,4,5,6,7,8,9 and 10 are written around a circle in arbitrary order. We add all the numbers with their neighbours, we get 10 sums that way. What is the maximum possible value of the smallest of these sums?
it is a known that a particular
machine will make product with
a qualified rate of 90% when it is
running well, but will do so with
a qualified rate of only 30% when
it is not running well. The
probability that machine is
running well is 75% normally .
Suppose that one day the first
product made by the machine is
qualified. Find the probabiliy
that the machine is running well at
this time.
three subject group are to be
formed randomly by 15 students
(including 3 girls) under the
condition that each groups
consist 5 students and each
student attends only one group.
flnd the probabilities that of the
following events (1) there is
exactly one girl in each group (2)
the 3 girls attend the same group
determinant (((old plate : EEU 874)),((new plate : 1BXK 267)))
Old California license plate
consisted of a sequence of
three letters followed by three
digits (see figure above).
Assuming that any sequence
of letters and digits was allowed
(though actually some combinations
of letters were disallowed), how
many license plate were
available ?
Eight eligible bachelor and seven beautiful
models happen randomly to have
purchased single seats in the same 15−seats
row of theather. On the average , how many
pairs of adjacent seats are ticketed
for marriageable couples ?
Five children sitting one behind
the other in a five seater merry−go−round
,decide to switch seats so that each
child has new companion in front.
In how many ways can this be done?
There are 20 persons at a party.
Maria dansed with 7 boys,
Stacy dansed with 8 boys,
Monia dansed with 9 boys and
Eve dansed with all the boys at the party.
How many girls are there at the party ?