Answer:
7/34
Step-by-step explanation:
Total number of chips in the bag = 8 + 7 + 2 = 17
⇒ P(blue) = 8/17
⇒ P(green) = 7/16 (since the first chip has not been replaced)
⇒ P(blue and green) = 8/17 x 7/16 = 7/34
In statistics, the 68–95–99.7 rule, also known as the three-sigma rule or empirical rule, states that nearly all values lie within three standard deviations of the mean in a normal distribution.
About 68.27% of the values lie within one standard deviation of the mean. Similarly, about 95.45% of the values lie within two standard deviations of the mean. Nearly all (99.73%) of the values lie within three standard deviations of the mean.
In mathematical notation, these facts can be expressed as follows, where x is an observation from a normally distributed random variable, μ is the mean of the distribution, and σ is its standard deviation:
P( μ – σ ≤ x ≤ μ + σ ) ≈ 0.6827
P( μ –2σ ≤ x ≤ μ + 2σ ) ≈ 0.9545
P( μ –3σ ≤ x ≤ μ + 3σ ) ≈ 0.9973
So here A = μ – σ = 78.7 – 3.5 = 75.2 (answer
Answer = 5 problems per minute
Because you do the number of problems divided by the minutes eg 35/7 = 5
15y...for 12 months = 15(12) = 180 <==
