The answer is 72 (--> second choice).
I can prove it without calculator so you believe me:
600 becuase 90/.30= 300 and 300*2 =600
Pythagoras
28^2-19^2= 423
Square root of 423 = 20.5669638
Answer = 20.5669638
x = number of hours
want to find probability (P) x >= 13
x is N(14,1) transform to N(0,1) using z = (x - mean) / standard deviation so can look up probability using standard normal probability table.
P(x >= 13) = P( z > (13 - 14)/1) = P(z > -1) = 1 - P(z < -1) = 1 - 0.1587 = 0.8413
To convert that to percentage, multiply 100, to get 84.13%
Since 4 nights cost $356, 356÷4=89, so one night costs $89. 7-4=3, so 89×3 is 267. 267+356 is 623. The total cost for 7 nights would be $623
