78 gallons is the same as 312 quarts
your missing some number to do the process
the first question you add all the sides
12ab will be the right answer.
Since 24a^3 = 12ab(2a^2)
And 36ab^2 = 12ab(3b)
Our number system is in base 10, which means that each digit has a value that is a multiple of 10.
For ex:
877 literally means
8 7 7 where each digit is multiplied by
10^ 2 10 ^1 10^0 respectively
which is 8 * 10^ 2 + 7 * 10^1 + 7 * 10^0 = 8 * 100 + 7 * 10 + 7 * 1 = 800 + 70 + 7 = 877
Binary is in base 2, so each of its digits (which can only be 0 or 1) are multiplied by multiples of 2 (2^0, 2^1, 2^2 ect.)
To find what 877 is in binary you can do the following:
the symbol : means divide and i'll write the quotient + the remainder
877 : 2 = 438 + 1 (438 is the quotient, 1 is the remainder)
438 : 2 = 219 + 0
219 : 2 = 109 + 1
109 : 2 = 54 + 1
54 : 2 = 27 + 0
27 : 2 = 13 + 1
13 : 2 = 6 + 1
6 : 2 = 3 + 0
3 : 2 = 1 + 1
1: 2 = 0 + 1
now write ALL off the remainders from BOTTOM to TOP:
1101101101
use a similar step for octal (use 8 instead of 2 as the divisor) and hexidecimal (use 16 instead of 2 as the divisor)