243 + 62-28 = n
243 + 34 = n
277 = n
n= 277
Basically you do fractions side by side. so, 6/3=15/h and then cross multiply to get your answer so that would give you 3h=80, then divide 80÷3
Answer:
E(X) = 6
Var(X) = 3.394
Step-by-step explanation:
Let X represent the number of carp caught out of the 20 fishes caught. Now, if we are to assume that each
of the (100, 20) ways to catch the 20 fishes will be equally likely.
Thus, we can say that X fulfills a hypergeometric
distribution with parameters as follows;
n = 20, N = 100, k = 30
Formula for expected mean value in hypergeometric distribution is;
E(X) = nk/N
E(X) = (20 × 30)/100
E(X) = 6
Formula for variance is;
Var(X) = (nk/N) × [((n - 1)(k - 1)/(N-1))) + (1 - nk/N)]
Var(X) = ((20 × 30)/100) × [((20 - 1)(30 - 1)/(100 - 1)) + (1 - (20 × 30/100)]
Var(X) = 6 × 0.5657
Var(X) = 3.394
The ratio of the height (h) of the streetlight to its distance to the end of Laura's shadow is the same as the ratio of Laura's height to her distance from the end of her shadow.
.. h/(12+9) = 5'4"/9
.. h = (21/9)*5'4" = 12 4/9 feet
.. h = 12 ft 5 1/3 inches
The streetlight is 12 ft 5 1/3 inches tall.
