Yes he is correcct because 4/8 and 1/2 is the same thing
If she picks 2/4 in half an hour she must pick 1.5 in an hour (2/4 x 2) so times that by 2 then its 3
Answer: 18
Explanation: Divide the diameter by 2.
(3x-4)(3x-4) is the answer because when something is squared, it's just multiplying itself by itself, this also applies to expressions.
We need to correctly choose exactly 4 out of the 6 drawn numbers.
Apply hypergeometric distribution:
a=number of correctly chosen numbers = 4
A=number of correct (drawn) numbers = 6
b=number of incorrectly chosen numbers = 2
B=number of undrawn numbers = 44-6 = 38
Then by the hypergeometric distribution
P(a,b,A,B)
=C(A,a)C(B,b)/C(A+B,a+b) [C(n,r)=combination of r objects taken out of n]
=C(6,4)C(38,2)/C(44,6)
=15*703/7059052
= 10545/7059052
= 0.001494 (to the nearest millionth)
Answer: probability of winning third prize is 10545/7059052=0.001494
