Answer:
7.4
Step-by-step explanation:
Answer:

Step-by-step explanation:
-5+2(10b-2)=31
Expand brackets.
-5+20b-4=31
-9+20b=31
Add 9 on both sides.
20b=40
Divide both sides by 20
b=2
It will be understood that population 6,000 billion (6*10^12) in 2017.
If this is not the case, follow the logic and the final number can be adjusted easily.
Mathematical answer:
In 2017: 6,000 billion=6000*10^9 =6*10^12
rate of increase = 1.3% per year (assumed constant)
final year = 2100
Population estimate in 2100
=6*10^12*(1.013^(2100-2017))
=6*10^12*(1.013^(83)
=6*10^12*(2.921352509198383)
=17.528*10^12
=17,528 billion.
Answer:
a) P = 362880 ways
b) P = 2880 ways
Step-by-step explanation:
a) We have four boys and five girls, they are going to sit together in a row of 9 theater seats, without restrictions
We have a permutation of 9 elements
P = 9!
P = 9*8*7*6*5*4*3*2*1
P = 362880 ways
b) Boys must seat together, we have two groups of people
4 boys they can seat in 4! different ways
P₁ = 4!
P₁ = 4*3*2*1
P₁ = 24
And girls can seat in 5! dfferent ways
P₂ = 5!
P₂ = 5*4*3*2*1
P₂ = 120
To get total ways in the above mentioned condition, we have to multiply P₁*P₂
P = 24*120
P = 2880 ways