How many athletes exercised more than 40 but less than 60 minutes

Mathematics

2 answers:

nika2105 [10]3 years ago

5 0

The correct answer is:

Explanation:

The number 40 is written in this stem-and-leaf plot as 4|0. 60 is written as 6|0. There are 4 leaves between these numbers; 5, 5, 5 and 5, with the stem of 4. This means the numbers are 45, 45, 45 and 45. There are only 4 between these two numbers.

BaLLatris [955]3 years ago

3 0

4. When reading the stem and leaf plot the only values that fall between the range of 40 < x <60 is the 4 values of 45. They are located at the tail end of the 4 stem after the zeros. The 40s and 60s are not counted because it is not mentioned equal to 40 or 60.

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A box contains 24 transistors,4 of which are defective. If 4 are sold at random,find the following probabilities. i. Exactly 2 a

zavuch27 [327]

SOLUTION

This is a binomial probability. For i, we will apply the Binomial probability formula

i. Exactly 2 are defective

Using the formula, we have

$\begin{gathered} P_x=^nC_x\left(p^x\right?\left(q^{n-x}\right) \\ Where\text{ } \\ P_x=binomial\text{ probability} \\ x=number\text{ of times for a specific outcome with n trials =2} \\ p=\text{ probability of success = }\frac{4}{24}=\frac{1}{6} \\ q=probability\text{ of failure =1-}\frac{1}{6}=\frac{5}{6} \\ ^nC_x=\text{ number of combinations = }^4C_2 \\ n=\text{ number of trials = 4} \end{gathered}$

Note that I made the probability of being defective as the probability of success = p

and probability of none defective as probability of failure = q

Exactly 2 are defective becomes the binomial probability

$\begin{gathered} P_x=^4C_2\times\lparen\frac{1}{6})^2\times\lparen\frac{5}{6})^{4-2} \\ P_x=6\times\frac{1}{36}\times\frac{25}{36} \\ P_x=\frac{25}{216} \\ =0.1157 \end{gathered}$

Hence the answer is 0.1157

(ii) None is defective becomes