When serenity runs the 400 meter dash, her finishing times are normally distributed with a mean of 90 seconds and a standard deviation of 2.5 seconds. using the empirical rule, determine the interval of times that represents the middle 95% of her finishing times in the 400 meter race.

[85, 95] seconds

Step-by-step explanation:

The empirical rule says 95% of the distribution is within 2 standard deviations of the mean. Two standard deviations is 2·(2.5 s) = 5 s, so 95% of her times are in the range 90 ±5 s. As an interval, that is [85, 95] seconds.

[85, 95] seconds

Step-by-step explanation:The empirical rule says 95% of the distribution is within 2 standard deviations of the mean. Two standard deviations is 2·(2.5 s) = 5 s, so 95% of her times are in the range 90 ±5 s. As an interval, that is [85, 95] seconds.

(a) the volume of the cone is 20/3 in3

hence, option a is correct.

answer: c, the green line

step-by-step explanation:

there is no black line, eliminate b.

simple interest implies periodic payments, but the red line shows no payments, eliminate d.

simple interest has equal payments. if paid say every day, the graph is about a straight line (actually a stairstep).

the yellow line is not straight, eliminate a.

check: the green line is straight, answer is c.

simple interest with positive interest rate gives a straight line sloping up to the right. green line:

g(t) = $100 + ($200-$100) ÷ (20 years) × (t years)

= $100 + (4%/year) × ($100)(t years)

incidentally, the yellow line curving upward represents continuously compounded interest

y = $100 × 2^(t years / (14 assuming the yellow line hits $200 at 14 years. 2^0 is 1, so y(0) = $100; 2^(14/14) is 2, so y(14) = $200.