A company 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?

Question

anonymous · Answer

(A) 19/20, (B) 47/50, (C) 13/20, (D) 43/50, (E) 17/20

anonymous · Answer

i would love to help but im working with probability right now and its confusing

anonymous · Answer

sorry

anonymous · Answer

That's OK thanks anyways tho!!

anonymous · Answer

kk

anonymous · Answer

@luigi0210 would you be able to assist me?

luigi0210 · Answer

Sorry, not good at this :(

anonymous · Answer

Ahhh, would you know someone who might be able too?

anonymous · Answer

Thanks anyways...

anonymous · Answer

@johnweldon1993 could you help me?

johnweldon1993 · Answer

Alright reading it confused me...but let me work through it

so 70% have touch screen
55% have HD capability
and 30% have both

"What is the probability that a smartphone chosen at random has either a touch screen or HD movie capability?"

Okay....well

Probability of (A or B) = P(A) + P(B) - P(A and B)

so we have

$$\large \frac{70}{100} + \frac{55}{100} - \frac{30}{100} = \frac{95}{100}$$

Looks like both are divisible by 5...so

$$\large \frac{19}{20}$$

anonymous · Answer

Thanks so much @johnweldon1993 your a lifesaver.

johnweldon1993 · Answer

No problem!