1) 1 digito -----> puede ser 7 numeros
2 digito ----->puede ser 7 numeros
9 digito ----->puede ser 9 numeros
el resto tienen 10 numeros cada digito
numeros diferentes=7*7*9*10*10*10*10*10*10*10=4410000000 (cuatro mil cuatrocientos diez millones) numeros diferentes
2) perro------------->3
gato---------------> 6
oso----------------> 2
<span>a) Seleccionar un perro, un gato y un oso.----------> 3*6*2=36 maneras
</span><span>b) Seleccionar un perro o un gato o un oso.--------> 3+6+2=11 maneras</span>
<span>It should be noted that in each day there are 24 hours which in turn is comprised of 60 minutes each. The way to answer this item to properly do the conversion and the dimensional analysis.
1. The equation that would be used in order to find out how many beats in one minute does an average human's heart do is,
x = (103,680 times/day)(1 day/24 hours)(1 hour/60 minutes)
Simplifying,
x = 72 times / minute</span>
When the person is less than 18 years old, out of 265 persons, 20 has job and 245 do not have job.
The probability is defined as 
.
Consider the first column only.
The probability that a randomly selected person surveyed has job is
2/3 of the 4/5 of the class has a dog and a cat. Just multiply
(2/3)(4/5)=8/15
45*(8/15)=24
