Answer:
Step-by-step explanation:
If we choose chairs having odd number in the row
no of chairs from which selection is made = 10
no of chairs to be selected = 5
no of ways = 10C₅
similarly if we choose hairs having even numbers only ,
similar to above , no of ways
= 10C₅
Total no of ways
= 2 x 10C₅
= 2 x 10 x 9 x 8 x 7 x 6 / 5 x 4x3 x 2 x 1
= 504 .
A heptagon has 7 sides.
Sum of all interior angles = (7 - 2) x 180 = 900°
900 - 776 = 124°
Answer: The final angle must be 124°
I used similarities in triangles
Answer:
Step-by-step explanation:
There are 20 ballots, 8 have drawn a car the rest are white.
Find the probability to extract at least one ballot with the drawing of a car if not replaced:
1. If a ballot is taken out:
8 have drawn a car: thus we have 8/20 = 2/5
2. If two ballots are removed, probability of extracting 1 ballot with drawing of car is 8/20 leaving 7 out of 19 remaining. The 7/19 is the probability of drawing out a second ballot with the drawing of a car. Thus we have
8/20 * 7/19 = 56/380 = 14/95
3. If three ballots are removed, probability of extracting 1 ballot with drawing of car is 8/20 leaving 7 out of 19 remaining. The 7/19 is the probability of drawing out a second ballot with the drawing of a car leaving 6 out of 18 remaining. The 6/18 is the probability of drawing out a third ballot with the drawing of a car.
8/20 * 7/19 * 6/18 = 42/855
