We must find UNIQUE combinations because choosing a,b,c,d... is the same as d,c,b,a...etc. For this type of problem you use the "n choose k" formula...
n!/(k!(n-k)!), n=total number of choices available, k=number of choices made..
In this case:
20!/(10!(20-10)!)
20!/(10!*10!)
184756
Answer:
3
Step-by-step explanation:
27 km
9 km every hour
so 27/9=3
The answer is 225
I got that by mulitplying .15 by 1500
Answer:
B
Step-by-step explanation:
Since x varies directly as y, the ratio of x to y remains the same. Let the value of x when y=4 be a. Then we have
We can cross multiply to get that
Answer:
40% finished, which means that 60% did not.
Step-by-step explanation:
a = p*w
12 = p*30
12/30=p
.40 = p
40%
