In a busy coffee shop, which is a member of an international chain of coffee shops, 40% of customers order a pastry in addition to their drink. if 20 customers were selected at random during one business day, what is the probability that at least 11 of them did not order a pastry with their drink. round your answer to 4 decimal places.

0.7553

Step-by-step explanation:

Given that in a busy coffee shop, which is a member of an international chain of coffee shops, 40% of customers order a pastry in addition to their drink.

Hence for 20 customers  selected at random during one business day,  x the no of customers who did not order a pastry with their drink is binomial since each customer is independent and there are only two outcomes.

X is binomial with n =20 and p = 1-0.4 = 0.60

q = 0.4

the probability that at least 11 of them did not order a pastry with their drink

=

Note that binomial prob

Step-by-step explanation:

a)

first step: find the gradient slope of line AB

A(-1,-2) B(7,2)

gradient=change in y/change in x

M=[2-(-2)]/[7-(-1)

M=4/8

M=1/2

the gradient of the straight line is given by

M1*M2=-1

1/2*M2=-1

multiply both sides by the reciprocal of 1/2

2*1/2*M2=-1*2

M2= -2.

b)

first find the mind point of line AB

A(-1,-2) B(7,2)

M.P=(x1+x2)/2 ,(y+y2)/2

M.P=(-1+7)/2 ,(-2+2)/2

M.P=6/2 ,0/2

M.P=3,0

ALSO THE GRADIENT PERPENDICULAR TO LINE AB IS;

M= -2

equation of a line perpendicular to AB and passes through the midpoint of AB

Y-Y1=M(X-X1). (3,0). M=-2

y-0=-2(x-3)

y= -2x+6