10 number of fingers and number of toes
1920 Founding of League of Nations
A Social Security Number has 9 Digits
6 Correct numbers to win the lottery
This ditloid is 5 = Number of Great Lakes.
f = 10n + (n - 1)^2 For n=10 f = 10(10) + (10 - 1)^2 f = 181
1993 the grand national that never was
13 M of N = 13 moons of neptune.
20 Bottles (of Champagne) in a Nebuchadnezzar
1 the Atomic Number of Hydrogen
To dilute a 3.0 N HCl solution to 0.2 N, you would need to dilute it 15 times (3.0 N / 0.2 N = 15). So, for 10 L of 3.0 N HCl, you would need to add 140 L of water to achieve a 0.2 N HCl solution (10 L * 15 = 150 L total, subtracting the original 10 L of HCl).
This is a Ditloid. The answer is 78 = Atomic Number of Platinum
50 is L in Roman Numerals