Answer:
a) 66
b) 45
Step-by-step explanation:
We have 12 horses and after the first race 2 of them have to be eliminated
that condition is equal to consider that 10 horses will be available for the second race.
The number of possiblities we have for the first race is the combination of 12 horses in group of 10
C¹²₁₀ = 12!/ (2!)* (12-2)! = 12*11/2 = 66
For the second race
C¹⁰₈ = 10! / 8! * (10-8)! = 10*9/ 2 = 45
Answer:
The exact value of tan(60°) is √(3).
Step-by-step explanation:
300=2×2×5×5×3
We observe that 2 and 5 are grouped in pairs and the 3 is left unpaired.
If we multiply 300 by the factor 3 then
300×3=2×2×5×5×3×3
900=2×2×5×5×3×3 which is a perfect square.
∴ Required number is 3
root of 900 =30
8/12: 2/3 and 16/24
6/8: 3/4 and 12/16
9/15: 3/5 and 18/30
2/16: 1/8 and 4/32
Answer: C. 
Step-by-step explanation:
Given: Box contains 8 green balls and 4 purple balls.
Total balls = 8+4 = 12
event 1 = first picking green ball
event 2 = second picking purple balls.
As first ball was replaced, that means both events are independent.
Probability that you have selected a green ball and then a purple ball = P(purple ball )
Formula for probability = 
Probability of selecting a purple ball (second pick)= 

The required probability
, so C is correct option.