Answer:
C = 10000n - 10000 ;
$110,000
Step-by-step explanation:
Given :
Cost = C
C partly varies as n ; C α n ; C = k1 * n = k1n
C partly constant = k2
Hence,
C = k1n + k2
For n = 8 ; C = 70000
For n = 10 ; C = 90000
8k1 + k2 = 70000 - - - - - (1)
10k1 + k2 = 90000 - - - - (2)
Subtract 1 from 2
8k1 - 10k1 = 70000 - 90000
-2k1 = - 20000
k1 = 10000
Put k1 = 10000 in (1)
8(10000) + k2 = 70000
80000 + k2 = 70000
k2 = 70000 - 80000
k2 = - 10000
The expression :
C = 10000n - 10000
Weekly cost for 12 people :
n = 12
C = 10000(12) - 10000
C = 120000 - 10000
C = $110,000