The sum of all prime factors of 100 is

100 = 2 + 3 + 5 + 7 + 11 + 13 + 17 + 19 + 23; that's the sum of the first 9 prime numbers.

...

If you convert 100 from base 10 to these other bases, you will get:

40 in BASE 25.

50 in BASE 20.

400 in BASE 5.

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value

6 adults and 9 children went.

a + c = 15

12a + 9c = 153

12(6) + 9(9) = 153

72 + 81 = 153