The largest number is 952. I'll tell you why...
7*8=56
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56*18=7*8*18=7*8*3*6=1008 (4 digits)
56*17=7*8*17=952 (3 digits)
18 times x = $75
I wasn’t able to find the multiplication sign on my keyboard and didn’t want to confuse you so I replaced x with times
Let x represent amount invested in the higher-yielding account.
We have been given that a man puts twice as much in the lower-yielding account because it is less risky. So amount invested in the lower-yielding account would be
.
We are also told that his annual interest is $6600 dollars. We know that annual interest for one year will be principal amount times interest rate.
, where,
I = Amount of interest,
P = Principal amount,
r = Annual interest rate in decimal form,
t = Time in years.
We are told that interest rates are 6% and 10%.


Amount of interest earned from lower-yielding account:
.
Amount of interest earned from higher-yielding account:
.

Let us solve for x.



Therefore, the man invested $30,000 at 10%.
Amount invested in the lower-yielding account would be
.
Therefore, the man invested $60,000 at 6%.
To solve this proportion:

Simplify 3/6, it reduces to 1/2

Then do the Criss cross method
1d = 7 ×2
d=14
Hope it helps!