As the variation is direct we have:

We must find the value of k.
For this, we use the following data:
y = 200 when x = 5
Substituting values we have:

Clearing k:

Then, the function is:

We evaluate the function for x = -3
Answer:
the value of y when x = -3 is:
c.
72
P = $70, p = 2.5% = 0.025
q = 1 + 0.025 / 12 = 1.002
Future value of a periodic deposit:
A = P · q · ( q^30 - 1 ) / ( q - 1 )
A = 70 · 1.002 · ( 1.002^30 - 1 ) / ( 1.002 - 1 )
A = $2,166
Answer:
He will have $2.166 in 30 months.