Answer:
M = 2.08 machine
Step-by-step explanation:

(A/P, 10%,15) is calculated from compound interest tables
= 400,000 (0.1315) + (10000)
= $62600
Let M be number of machines

AE(10%) = ($40,000 - 10,000) M - $62600 = 0
SOLVING FOR M
30000 M = 62600
M = 2.08 machine