—
To explain — 's correct help a bit more: In cases like these just think about what you're trying to achieve mathematically.
100 to 600 in 50's increments.
range you need: 600 - 100 = 500
steps you need: 500 / 50 = 10 => + 1 = 11 (the incremments plus starting at zero)
producing 11 numbers from 0 to 10 inclusive: int(random(0,11))//or shorter: int(random(11))
random(0, 11) produces floats that are higher than 0 and lower than 11, e.g. 0.023 or 10.98
int() omits the fractional part => 0.023 becomes 0, 10.98 becomes 10
0 to 10 * 50 => a range of 500 in 50's increments
+ 100 => shifting to the desired start value of 100