This would be my guess.

Assumptions:

30 lbs x 0.45359237 kg/lbs = 13.6 kg (sorry Im Canadian!)

American Currency Weight:

Penny weight = 2.5g = 0.0025kg

Nickel weight = 5.0g = 0.005kg

Dime weight = 2.268g = 0.002268kg

Quarter weight = 5.670g = 0.005670kg

Therefore, since there is an even mixture of all coins:

0.0025p + 0.005n + 0.002268d + 0.005670q = 13.6

Where, p = penny, n = nickel, d = dime, q = quarter

But, p = n = d = q = x

0.0025x + 0.005x + 0.002268x + 0.005670x = 13.6

0.015438x = 13.6

x = 880 (rounding down)

Therefore, an equal mixture contains 880 of each penny, nickel, dime, and quarter.

Therefore in 13.6 kg or 30 lbs we have:

880 * pennys = $8.80

880 * nickels = $44.00

880 * dimes = $88.00

880 * quarters = $220.00

For a grand total of : $360.8 / 30 pounds of mixed coins.

Therefore, in 1 pound of mixed coins, the monetary value should approximately be $12.03.

Hope that helps!

so for q with a weight of 5.67g we would get a weight of 17.01g and a price of .75$
for d with a weight of 2.268g we would get a weight of 4.536g and a price of .20$
for n with a weight of 5g we would get a weight of 5g and a price of .05$
for p with a weight of 2.5g we would get a weight of 10g and a price of .04$

total weight = 36.456g = .036456kg
total price = .94$

so $/kg = 25.721$/kg = {{{11.66684 $/lb}}}