USE PHOTOMATH , it will solve it and show you how to do it , I use it for maths questions like this !!!!!!
Answer:
a) 0.00031
b) 0.0017
c) 0.31
d) 0.00018
Step-by-step explanation:
attached below is the detailed solution
Total number of 7-poker cards are 52P7 = 133784560
A) Determine the probabilities of Seven-card straight
probability of seven-card straight = 0.00031
B) Determine the probability of four cards of one rank and three of a different rank
P( four cards of one rank and three of different rank ) = 0.0017
C) Determine probability of three cards of one rank and two cards of each two different ranks
P( three cards one rank and two cards of two different ranks ) = 0.31
D) Determine probability of two cards of each of three different ranks and a card of a fourth rank
P ( two cards of each of three different ranks and a card of fourth rank ) = 0.00018
The rule of geometric sequence is ⇒⇒⇒ a * r^(n-1)
Where a is the first term and r is the common ratio
for the given sequence √5 , √10 , 2√5 , .......
a = √5
r = √10 / √5 = √2
The ninth term = √5 * (√2)^(9-1) = √5 * (√2)⁸ = 16 √5
the correct answer is the third option 16√5
Using Pythagorean theorem





Remark
The thing you must not do is write 7.182 as your answer. That is the exact answer found using a calculator.
What to do.
What you should do is multiply two rounded numbers together.
7.6 rounded is 8 roughly
0.945 is almost 1.
Your answer is 8*1 = 8 roughly. This skill is very handy when you are writing a test and you want to see if you've done the question correctly. It is easy to misplace a decimal or put in incorrect digits and this is a quick check on things like that.