Question

Katie has a 75% chance of making an A on a test. What is the probability that she will not make an A on her next two test: Algebra and Physics?
A) 3.125%
B) 6.25%
C) 12.5%
D) 25%

Answer 1

I am pretty sure it's B 6.25% but I'm not exactly sure

Answer 2

Answer: B) 6.25%

Step-by-step explanation:

Let T be the event of making grades on a test by Katie.

Given: The probability that she will not make an A on test P(T)=75%= 0.75

The probability that she will not make an A on test is given by :-

$P(T)'=1-P(T)\\\\\\Rightarrow\ P(T)'=1-0.75\\\\\Rightarrow P(T)=0.25$

Since all the events of making grades are independent.

Therefore, the probability that she will not make an A on her next two test: Algebra and Physics is given by :-

$P(\text{Algebra and Physics})=P(T)\times P(T)\\\\\Rightarrow0.25\times0.25=0.625$

In percent, $0.625\times100=6.25\%$

Hence, the probability that she will not make an A on her next two test: Algebra and Physics = 6.25%.