Complete Question
The complete question is shown on the first uploaded image
Answer:
The correct option is B
Explanation:
The number of alphabet is n= 4 (a , b , c , d )
Generally the total number of string of length 10 over the 4 alphabets is

Gnerally the number of string of length 10 that does not include b is
Generally the number of strings of length 10 over the 4 alphabets that have at least one alphabet b somewhere in the string is

=> 
Answer:
The minimum total speed is 11.2km/s
Explanation:
We are been asked to find the escape velocity.
Escape velocity is defined as the minimum initial velocity that will take a body(projectile)away above the surface of a planet(earth) when it's projected vertically upwards.
The formula to calculate the escape velocity is Ve = √2gR
For the earth g = 9.8m/s2 , R = 6.4*10^6
Substituting into the equation Ve = √2*9.8*6.4*10^6 = 11.2*10^3m/s
=11.2km/s
Answer:
ENQUIRE is the answer
Explanation: google....internet browser-.. .-.
Answer:
d. observing sunspots on the Sun and mountains on the Moon
Explanation:
Galileo was an Italian Physicist and Astronomer and is regarded as the father of modern Physics.
It was previously believed that the objects in the heavens such as the sun, moon and stars were perfect and rough till he observed sunspots on the sun and mountains on the moon which indicates the surface of the moon is rough with mountains and craters.