The lifetime of a 2-volt non-rechargeable battery in constant use has a normal distribution with a mean of 516 hours and a standard deviation of 20 hours. the proportion of batteries with lifetimes exceeding 520 hours is approximately

a. 0.4207
b. 0.2000
c. 0.5793

A. 0.4207

Step-by-step explanation:

Given : The lifetime of a 2-volt non-rechargeable battery in constant use has a Normal distribution with a mean of 516 hours and a standard deviation of 20 hours.

i.e.

Let x denotes the lifetime of a 2-volt non-rechargeable battery in constant use.

Then , the probability of batteries with lifetimes exceeding 520 hours is approximately:-

Hence, the proportion of batteries with lifetimes exceeding 520 hours is approximately 0.4207.

∴ Correct option is A. 0.4207

idk this answer sorry cant on this one.

step-by-step explanation:

the number of possible outcomes that do not show a 1 on the first spinner and show the number 4 on the second spinner is 2.

spinner 1 spinner 2

1                     1

1                     2

1                     3

1                     4

2                   1

2                   2

2                   3

2                   4   = not 1, and 4

3                   1

3                   2

3                   3

3                   4 = not 1, and 4

only 2 outcomes have passed the given condition.

step-by-step explanation: