Acompany that manufactures smartphones makes 70% of the phones with a touch screen and 55% of the phones with hd movie capability. 30% of the phones have both a touch screen and hd movie capability. what is the probability that a smartphone chosen at random has either a touch screen or hd movie capability?

Option: A is the correct answer.

Step-by-step explanation:

A company manufactures 70% touch screen phones.

55% have HD capability.

and 30% have both touch screen and HD capability.

Let A denote the touch screen phones.

B denote the HD capability.

C denote the both touch and HD capability.

Now we are asked to find the probability that a smartphone chosen at random has either a touch screen or HD movie capability:

i.e.. we have to find P(A∪B)

we know that:

P(A∪B)=P(A)+P(B)-P(A∩B)

Hence,

Hence, option: A is correct.

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional