Answer:
$34.47
Step-by-step explanation:
You want the monthly payment starting at age 25 that will result in an account value of $70,000 at age 60 if the account earns 7.5% interest compounded monthly.
The monthly payment P that will result in account value A after n years earning interest at annual rate r is given by ...
[tex]P=\dfrac{Ar}{12((1+r/12)^n-1)}\\\\\\P=\dfrac{70000\cdot0.075}{12(1.00625^{420}-1)}\approx34.4698[/tex]
Your monthly payment will be $34.47.
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Additional comment
At 12 payments per year for 60-25 = 35 years, the number of payments is 12·35 = 420.