+0

-2
53
3
+25

(a) Simplify $$\frac{\binom{n}{k}}{\binom{n}{k - 1}}$$

(b) In the expansion of $$(1 + x)^n$$ there exist three consecutive coefficients $$a,b,c$$ that satisfy $$a:b:c = 1:7:35$$. Find the positive integer $$n$$.

Thank youuuu!

Mar 26, 2020

#1
+1970
0

a) Note that a combination is n!/(r)!*(n-4)!

We can write the equation in this form, and then simplify.

Hope this helped!

Mar 26, 2020
#2
+111330
+1

Heureka   gives some good answers here :

https://web2.0calc.com/questions/help_73560#r2

Mar 26, 2020
#3
+1970
+2

Yes, definitely!!!!!!!

Mar 26, 2020