The time it takes me to wash the dishes is uniformly distributed between 8 minutes and 17 minutes.

Mathematics

1 answer:

Sergeu [11.5K]3 years ago

7 0

The time it takes to wash has the probability density function,

$P(X=x) = \begin{cases}\frac1{17-8}=\frac19&\text{for }8\le x\le 17\\0&\text{otherewise}\end{cases}$

The probability that it takes between 14 and 16 minutes to wash the dishes is given by the integral,

$\displaystyle\int_{14}^{16}P(X=x)\,\mathrm dx = \frac19\int_{14}^{16}\mathrm dx = \frac{16-14}9 = \frac29 \approx \boxed{0.22}$

If you're not familiar with calculus, the probability is equal to the area under the graph of P(X = x), which is a rectangle with height 1/9 and length 16 - 14 = 2, so the area and hence probability is 2/9 ≈ 0.22.

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Step-by-step explanation:

Absolute Value Inequality

Assume the actual width of a safety belt strap for a certain automobile is x. We know the ideal width of the strap is 6 cm. This means the variation from the ideal width is x-6.

Note if x is less than 6, then the variation is negative. We usually don't care about the sign of the variation, just the number. That is why we need to use the absolute value function.

The variation (unsigned) from the ideal width is:

$|x-6|$