Answer:
3876
Step-by-step explanation:
Given the following :
Fraternity members = 20
They are to attend 5 different parties in groups of 4
Meaning a group = 4 persons
Atleast one brother will attend exactly one of the parties. (the brothers are indistinguishable).
Then, exactly one brother at a party (20 - 1) = 19, since they are indistinguishable.
Group members are in 4's
19C4
From: nCr = n! /(n-r)! r!
19C4 = 19! / (19 - 4)! 4!
= 19! / 15! 4!
= (19 * 18 * 17 * 16) / (4 * 3 * 2)
= 93024 / 24
= 3876
Answer:
The bike whose position has greater y-coordinate.
Step-by-step explanation:
If Dorrian plotted the co-ordinates of the bikes with second on the x-axis and distance traveled on the y-axis, the x-coordinates of the two bikes will be the same.
But, the bike which went faster will have the greater y-coordinate and which followed the earlier will have the smaller y-coordinate.
Hence, the bike which has greater y-coordinate will win the race.
11, 12, 13, 14, 15, 16, 17, 18, 19 Sorry if it doesn't help, I'm being too obvious
We have an arithmetic progression:
Nth=an
an=a₁+(n-1)d
a₁ is the first term.
n=number of terms.
d=common difference
10,17,24,31...
a₁=10
d=a₂-a₁=17-10=7
Therefore:
Nth=an
an=a₁+(n-1)d
an=10+(n-1)7
an=10+7n-7
an=7n+3.
Therefore: the formula for the nth is, an=a+(n-1), in this case; an=7n+3,
To check:
a₁=7*1+3=10
a₂=7*2+3=17
a₃=7*3+3=24
a₄=7*4+3=31
a₅=7*5+3=38.......
Answer:
First look at the number of bricks alone.
Going from 50 bricks to 60 bricks is more work, thus it will require more people. The number of people would be the ratio of the 2. Since the number must be larger, you know the numerator must be the larger of the 2 numbers, so you get 60/50
Next look at the time alone.
Going from 30 minutes to 20 minutes is more work, thus it will require more people. The number of people would be the ratio of the 2. Since the number must be larger, you know the numerator must be the larger of the 2 numbers, so you get 30/20
Now you can just multiply everything.
= 5*60/50*30/20
= 5*6/5*3/2
= 90\10
= 9.
