Last week, my youngest sister and other seven hundred thousand high school students in Indonesia are fighting for their seats in University. If the years before the score is deducted by one for answering wrong, fortunately, this year you’ll no longer get penalized.
So, with 150 mutiple choice questions with 5 choices each, a probability mass function of binomial distribution with
p = 0.2, n = 150, and k = 0, 1, 2, ..., n illustrates the outcomes if you are guessing randomly all the answers.
Randomly guessing will get us somewhere around 14-49 questions correct and most probably it will be around 30 questions correct. It’s impossible to get either all questions correct or wrong. Struck by lightning 7 times during your lifetime has much much better chance happened. Good luck, Vira!