Question

A number is selected randomly from the integer from 10to30 what is the probability of picking a multiple of 4or5​

Answer 1

`(3)/(7)`

Explanation:

Start by finding how many integers there are from 10-30...

30-10+1=20+1=21

Note we have to add 1 since it is inclusive.

Now, let's find how many multiples of 4 or 5 there are from 10-30...

4*3=12

4*4=16

4*5=20

4*6=24

4*7=28

5*2=10

5*3=15

5*4=20

5*5=25

5*6=30

5+5-1=9

Note we have to subtract 1 since 20 is counted twice.

The probability would be...

`(Multiples\ of\ four\ and\ five\ from\ 10-30)/(Amount\ of\ integers\ between\ 10-30)=(9)/(21)=(3)/(7)`