There are 10 seniors in the class, from which 4 should be chosen by the teacher. The order of the chosen students does not matter. This means that we speak of combinations. THe equation for calculating the number of possible combinations is:
C=N!/R!(N-R), where N is the total number of objects and R is the number of objects we select from the N
In our case, N=10, R=4.
C= 10!/4!*6!=10*9*8*7*6!/6!*4*3*2*1=<span>10*9*8*7/24=5040/24=210
There are 210 different ways for the teacher to choose 4 seniors in no particular order.</span>
The answer is 0.5 hours.
A velocity (v) of an object is a distance (d) divided by time (t):
v = d ÷ t ⇒ t = d ÷ v
It is given:
v1 = 192 km/h
v2 = 960 km/h
t1 - t2 = 2h
We need to calculate t2.
Since they will travel the same distance before the jet overtakes the plane, we can say that d1 = d2 = d
Now, let's express t1 and t2:
t1 = d/192
t2 = d/960
Therefore: d/192 - d/960 = 2
The least common denominator is 960, so:
5d/960 - d/960 = 2
4d/960 = 2
4d = 2 · 960
4d = 1920
d = 1920 ÷ 4 = 480 km
Now t2 = d/960 = 480/960 = 0.5 hours.
Each increases by a certain amount called the common difference
4.4-2.8=1.6
6-4.4=1.6
7.7-6=1.7
hmm, some error
maybe you meant 7.6
common difference is 1.6
answer is C