When n = 1 first term = -6
n = 2 second term = 0
n = 3 third term = 6
n = 4 4th term = 12
so we have an Arithmetic sequence first term = -6 and common difference = 6
Sum 14 terms = (14/2)[2*-6 + (14-1)*6]
= 462 answer
Find total instruments:
20+20+45+15 = 100
20 are brass
The portion would be number of brass over total:
20/100 which reduces to 1/5 are brass
Answer:
= 11.66 units
Step-by-step explanation:
distance between 2 points (a,b) and (c,d) = 
= 
=
= 11.66 units
7/8 = 21/24
5/12 = 10/24
21/24-10/24 = 11/24